Effects of glucosamine-chondroitin combination on synovial fluid IL-1β, IL-6, TNF-α and PGE2 levels in internal derangements of temporomandibular joint

Can treatment with chondroitin and glucosamine sulphate prevent changes in the articular disc caused by temporomandibular joint osteoarthritis?

BACKGROUND

Chondroitin and glucosamine sulphates (CGS) are considered structure-modifying drugs and have been studied in the prevention, delay or reversal of structural morphological changes in joints caused by osteoarthritis.

OBJECTIVE

The aim of the present study was to investigate the action of CGS on the progression of chemically induced osteoarthritis in the temporomandibular joint (TMJ) of rabbits by evaluating the serum levels of tumour necrosis factor (TNF-α) and collagen in the articular discs.

MATERIALS AND METHODS

A sample of 36 male rabbits was divided into three groups: control (CG), osteoarthritis (OG) and treatment (TG). The disease was induced by intra-articular injection of sodium monoiodoacetate (10 mg/mL) in the OG and TG groups bilaterally. After 10 days, the TG animals received subcutaneous injection of chondroitin sulphates and glucosamine (7.5 mg/kg) and the OG and CG received saline solution (50 μL). Euthanasia times were subdivided into 40 and 100 days. Collagen quantification was performed by biochemical and histological analysis and for the quantification of serum levels of TNF-α, an enzyme immunoassay was used.

RESULTS

The TG showed an increase in the collagen area of the articular disc when compared to the CG and the OG. The increase collagen concentration in the discs did not show a statistically significant difference between the groups. Post-treatment TNF-α levels were significantly lower in TG compared to OG.

CONCLUSIONS

The results indicate that CGS treatment delayed the degeneration of the collagen in the TMJ articular disc and reduced serum TNF-α levels, indicating a preventive effect on OA progression.

Effects of Conditioned Media From Human Umbilical Cord-Derived Mesenchymal Stem Cells on Tenocytes From Degenerative Rotator Cuff Tears in an Interleukin 1β-Induced Tendinopathic Condition

Background

Evidence suggests that mesenchymal stem cells (MSCs) are safe for treating different tendinopathies. Synovial fluid is a pooled environment of biomarkers from the inflammatory and degenerative joint cavity. Understanding the effects of synovial fluid on MSCs is important, as it is the first microenvironment that administered MSCs encounter. Several studies have reported that exposure to osteoarthritic synovial fluid-activated MSCs increased the release of soluble factors; however, the paracrine effects of shoulder synovial fluid-stimulated umbilical cord-derived MSCs (SF-UC-MSCs) on tendinopathy have yet to be investigated.

Purpose

To assess the effects of the conditioned media from SF-UC-MSCs on tenocytes from degenerative rotator cuff tears in an interleukin-1β (IL-1β)-induced tendinopathic condition.

Study Design

Controlled laboratory study.

Methods

UC-MSCs were isolated and cultured from healthy, full-term deliveries by cesarean section. Tenocytes were isolated and cultured from patients with degenerative rotator cuff tears. Conditioned media were obtained from UC-MSCs stimulated with synovial fluid. To evaluate the gene expression of proinflammatory and anti-inflammatory cytokines, enzymes and their inhibitors, matrix molecules, and growth factors, the tenocytes were cultured with IL-1β and 50% of the conditioned media from the SF-UC-MSCs; quantitative, real-time, reverse transcriptase polymerase chain reaction was also performed. A prostaglandin E2 (PGE2) assay was performed to investigate the PGE2 level secreted by the tenocytes. Western blotting was performed to examine protein synthesis of collagen type I and III. Cell viability, senescence, and apoptosis assays were also performed.

Results

The conditioned media from the SF-UC-MSCs interfered with the inflammatory gene expression on tenocytes induced by IL-1β, but it increased the gene expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-3. Meanwhile, the conditioned media decreased the PGE2 level on cells induced by IL-1β. It did increase the type I/III ratio of gene expression and protein synthesis, mainly through the induction of type I collagen. Conditioned media of SF-UC-MSCs reversed senescence and apoptosis induced by IL-1β.

Conclusion

Study findings indicated that the conditioned media from SF-UC-MSCs had anti-inflammatory effects and cytoprotective effects on IL-1β-treated tenocytes from degenerative rotator cuff tears.

Clinical Relevance

UC-MSCs have useful potential for the treatment of tendinopathy in practice.

Nutritional Strategies for Chronic Craniofacial Pain and Temporomandibular Disorders: Current Clinical and Preclinical Insights

This narrative review provides an overview of current knowledge on the impact of nutritional strategies on chronic craniofacial pain associated with temporomandibular disorders (TMDs). Individuals experiencing painful TMDs alter their dietary habits, avoiding certain foods, possibly due to chewing difficulties, which might lead to nutrient deficiencies. Our literature investigation revealed that the causal links between nutritional changes and craniofacial pain remain unclear. However, clinical and preclinical studies suggest that nutraceuticals, including vitamins, minerals, polyphenols, omega-3 fatty acids, isoprenoids, carotenoids, lectins, polysaccharides, glucosamines, and palmitoylethanolamides, could have beneficial effects on managing TMDs. This is described in 12 clinical and 38 preclinical articles since 2000. Clinical articles discussed the roles of vitamins, minerals, glucosamine, and palmitoylethanolamides. The other nutraceuticals were assessed solely in preclinical studies, using TMD models, mostly craniofacial inflammatory rodents, with 36 of the 38 articles published since 2013. Our investigation indicates that current evidence is insufficient to assess the efficacy of these nutraceuticals. However, the existing data suggest potential for therapeutic intervention in TMDs. Further support from longitudinal and randomized controlled studies and well-designed preclinical investigations is necessary to evaluate the efficacy of each nutraceutical intervention and understand their underlying mechanisms in TMDs.

Intra-Articular Injectable Biomaterials for Cartilage Repair and Regeneration

Osteoarthritis is a degenerative joint disease characterized by cartilage deterioration and subsequent inflammatory changes in the underlying bone. Injectable hydrogels have emerged as a promising approach for controlled drug delivery in cartilage therapies. This review focuses on the latest developments in utilizing injectable hydrogels as vehicles for targeted drug delivery to promote cartilage repair and regeneration. The pathogenesis of osteoarthritis is discussed to provide a comprehensive understanding of the disease progression. Subsequently, the various types of injectable hydrogels used for intra-articular delivery are discussed. Specifically, physically and chemically crosslinked injectable hydrogels are critically analyzed, with an emphasis on their fabrication strategies and their capacity to encapsulate and release therapeutic agents in a controlled manner. Furthermore, the potential of incorporating growth factors, anti-inflammatory drugs, and cells within these injectable hydrogels are discussed. Overall, this review offers a comprehensive guide to navigating the landscape of hydrogel-based therapeutics in osteoarthritis.

Effects of Glucosamine in the Temporomandibular Joint Osteoarthritis: A Review

Osteoarthritis in the temporomandibular joint (TMJ) is a chronic disease characterized by irreversible damage to articular surfaces, including inflammation, loss of articular cartilage, and subchondral bone alterations, which would be radiographically evident only in later stages. Symptomatic slow-acting so-called nutraceutical drugs have been proposed as a treatment for osteoarthritis in comparison to non-steroidal anti-inflammatory drugs (NSAID) because of their appreciable safety profile even in long-term intake. Glucosamine, being one among them, proved highly efficient in knee osteoarthritis. However, its application in TMJ osteoarthritis dates back only to 2001 and is still inconclusive in its efficiency even with systematic reviews, in restoring the structural and functional aspects of damaged TMJ. Glucosamine, being a natural compound and also a contributor to building the matrix of articular cartilage, can be utilized effectively for TMJ osteoarthritis as an adjunct along with other conventional treatment modalities available till now, which also have moderate prognosis in most of the clinical scenarios. This review summarizes data relating to the mechanism of osteoarthritis and its management using glucosamine formulations. The beneficial effects of glucosamine on the pathophysiology of TMJ osteoarthritis are possibly due to its contribution to hyaluronic acid regulation and in establishing a proper balance between anabolism/catabolism in the articular tissues.

The Effect of Arthrocentesis Treatment for Maximum Mouth Opening and Pain in Temporomandibular Joint Diseases and the Effect of Splint, Drug, and Physical Therapy on This Treatment

Background and Purpose: Temporomandibular disorders (TMD) are a heterogeneous group of musculoskeletal and neuromuscular diseases involving the temporomandibular joint complex and the surrounding muscle and osseous structure. TMD can be classified as intra-articular or extra-articular. The aim of this study was to evaluate the effect of arthrocentesis in terms of maximum mouth opening (MMO) and pain in patients with TMD of intra-articular origin. In addition to this treatment, the effects of factors such as splints, medication, and physical therapy on arthrocentesis were examined. Material and methods: This retrospectively designed study was conducted with 79 patients who had previously undergone arthrocentesis. These patients were divided into three groups according to the Research Diagnostic Criteria for temporomandibular disorder: disc displacement (DD) with locking (Group 1), DD without locking (Group 2), and degenerative joint diseases (Group 3) groups. The maximum mouth opening (MMO) and visual analog score (VAS) values of the groups were recorded before arthrocentesis (Baseline: T0), on the third day after arthrocentesis (T1), and at the sixth month (T2) after arthrocentesis. Information about whether the patients received concurrent medical treatment, splint treatment, and physical therapy was also recorded. These data were compared between groups. Results: It was observed that the VAS scores in all three groups decreased from T1 compared to T0 (p < 0.05). Likewise, the MMO value increased in all groups at T1 compared to T0. (p < 0.05). It was observed that splint treatment, pain killer and muscle relaxant treatment, and physical therapy made no additional contribution to arthrocentesis in terms of reducing pain or increasing MMO value (p > 0.05). Conclusions: Arthrocentesis was observed to be effective in terms of pain and function in TMJ patients in this study. It was observed that splint therapy, physical therapy, and medical therapy made no additional contribution to arthrocentesis in terms of MMO or pain.

Low-level Cu-fortification of bovine lactoferrin: Focus on its effect on in vitro anti-inflammatory activity in LPS-stimulated macrophages

Bovine lactoferrin (LF) per 1 g was reacted with 0.16, 0.32, and 0.64 mg CuCl₂ to reach 10%, 20%, and 40% copper-saturation, respectively, aiming to assess their anti-inflammatory activities to lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The macrophages treated with CuCl₂ at 0.051 μg/mL dose did not have obvious change in cell viability, lactate dehydrogenase (LDH) release, and intracellular reactive oxygen species (ROS) production. However, LF and Cu-fortified LF products (10-80 μg/mL doses) mostly showed inhibitory effects on the stimulated macrophages dose-dependently. Moreover, Cu-fortified LF products of lower Cu-fortifying levels at lower doses exerted weaker inhibition on the stimulated macrophages than LF, leading to higher cell viability but decreased LDH release. Meanwhile, LF and Cu-fortified LF products at 10 and 20 μg/mL doses showed different activities to the stimulated cells, via partly decreasing or increasing the production of inflammatory mediators namely prostaglandin E₂ (PGE₂), nitric oxide, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and ROS production, depending on the used Cu-fortifying and dose levels. Compared with LF, Cu-fortified LF product (Cu-fortifying level of 0.16 mg/g LF) at 10 μg/mL dose showed enhanced inhibition on the production of PGE₂, ROS, IL-1β, and TNF-α, evidencing increased anti-inflammatory activity. However, the inhibition of Cu-fortified LF product (Cu-fortifying level of 0.32 mg/g LF) at 20 μg/mL dose on the production of these inflammatory mediators was mostly reduced. It is thus proposed that both Cu-fortifying and dose levels could affect LF's anti-inflammatory activity in LPS-stimulated macrophages, while the Cu-fortifying level of LF could govern activity change.

Oral Glucosamine in the Treatment of Temporomandibular Joint Osteoarthritis: A Systematic Review

Temporomandibular disorders (TMDs) occur frequently within the general population and are the most common non-dental cause of orofacial pain. Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative joint disease (DJD). There have been several different methods of treatment of TMJ OA listed, including pharmacotherapy among others. Due to its anti-aging, antioxidative, bacteriostatic, anti-inflammatory, immuno-stimulating, pro-anabolic and anti-catabolic properties, oral glucosamine seems to be a potentially very effective agent in the treatment of TMJ OA. The aim of this review was to critically assess the efficacy of oral glucosamine in the treatment of TMJ OA on the basis of the literature. PubMed and Scopus databases were analyzed with the keywords: (temporomandibular joints) AND ((disorders) OR (osteoarthritis)) AND (treatment) AND (glucosamine). After the screening of 50 results, eight studies have been included in this review. Oral glucosamine is one of the symptomatic slow-acting drugs for osteoarthritis. There is not enough scientific evidence to unambiguously confirm the clinical effectiveness of glucosamine supplements in the treatment of TMJ OA on the basis of the literature. The most important aspect affecting the clinical efficacy of oral glucosamine in the treatment of TMJ OA was the total administration time. Administration of oral glucosamine for a longer period of time, i.e., 3 months, led to a significant reduction in TMJ pain and a significant increase in maximum mouth opening. It also resulted in long-term anti-inflammatory effects within the TMJs. Further long-term, randomized, double-blind studies, with a unified methodology, ought to be performed to draw the general recommendations for the use of oral glucosamine in the treatment of TMJ OA.

Evaluation of Local Application of Glucosamine Sulfate and Chondroitin Sulfate on Temporomandibular Joint Response and Alleviation of Pain and Tension During the Functional Treatment of Skeletal Class II Patients: A Randomized Control Clinical Trial

OBJECTIVE

 This study was conducted to assess the effects of applying a gel of combined glucosamine sulfate and chondroitin sulfate on the temporomandibular joint (TMJ) area in patients with skeletal Class II malocclusion treated by removable functional appliances in terms of TMJ internal proportions, levels of pain, and tension.

MATERIALS AND METHODS

The study included 36 patients aged 10-13 years with skeletal Class II malocclusion due to retrusion of the mandible characterized by: 4-8 degrees of the sagittal skeletal discrepancy (ANB) angle, 4-7 mm of overjet, 72-76 degrees of the sagittal mandibular positioning (SNB) angle, and a bone maturity stage located at pubertal growth spurt. Patients were distributed to the experimental group (Twin-Block appliance + Jointance® gel) or the control group (conventional treatment with the Twin-Block appliance). An allocation ratio of 1:1 was employed. Pre- and post-treatment digital lateral cephalometric radiograms were taken, and the TMJ joint spaces were measured using the Viewbox software (dHAL Software, Kifissia, Greece). The pain and discomfort levels were evaluated using a questionnaire with a four-point Likert scale at three assessment times.

RESULTS

 The anterior and posterior glenoid and anterior condylar distances to the pterygoid vertical (PTV) reference plane significantly decreased after treatment (p<.001), and the anterior joint space decreased significantly (p<.001). In contrast, the superior distance of the condyle to the Frankfort horizontal reference plane increased significantly after treatment, and the same results were found for the posterior and superior joint spaces (p<.05). There were no significant differences between the two groups in the evaluated linear variables. No significant differences were found when comparing pain and tension levels between the two groups at each assessment time. A gradual decrease in pain and tension levels was observed between the three evaluation times in both groups.

CONCLUSIONS

 A combination of glucosamine sulfate and chondroitin sulfate did not affect the temporomandibular joint spaces, pain, and tension levels in patients with skeletal Class II malocclusions treated by removable functional appliances.

Clinical Evaluation of Intra-Articular Injection of Chondroitin Sulfate and Sodium Hyaluronate in the Management of Degenerative Osteoarthritis of Temporomandibular Joint

AIM: This study aims to evaluate the effectiveness of intra-articular injection of chondroitin sulfate and sodium hyaluronate in cases of temporomandibular joint (TMJ) degenerative osteoarthritis. MATERIAL AND METHODS: Thirty patients ASA I of both sexes, who were selected from outpatient clinic of Oral Surgery Department, Faculty of Dentistry – Suez Canal University, complaining of painful TMJ, presence of unilateral or bilateral TMJ pain, impairment of jaw movements, and joint sounds. Clinical examination was performed to all patients and pre-operative measurements of visual analog scale (VAS) for morning pain, pain with movement and spontaneous pain, maximum mouth opening, and presence or absence of clicking. Patients were randomly divided into two groups; (a) Study group consisted of 15 patients, they had intra-articular injection of chondroitin sulfate and sodium hyaluronate once weekly for 3 weeks and (b) control group consisted of 15 patients, they had intra-articular injection of sodium hyaluronate once weekly for 3 weeks. Post-operative measurements of VAS for previous pain types, maximum mouth opening, and clicking were obtained at 1 month, 3 months, and 6 months post-injection. RESULTS: There was a statistically significant reduction of all types of pain in the study group compared to the control group at all time intervals (p ≤ 0.05), for maximum mouth opening, there was a significant improvement in mouth opening in the study group for all time intervals (p ≤ 0.05), but for the clicking, there was not statistically significant difference between the study and control groups after 1 month, 3 months, and 6 months. The difference between groups was barely statistically significant (p = 0.05). CONCLUSION: Intra-articular injection of a combination of chondroitin sulfate and sodium hyaluronate is an effective tool in reducing pain, clicking, limited mouth opening, and other symptoms associated with degenerative TMJ diseases.

Pre-clinical Investigation of Protective Effect of Nutraceutical D-Glucosamine on TNBS-induced Colitis

The level of precursors involved in the biosynthesis of glycosaminoglycan (GAG), glucosamine synthase, and N-acetyl glucosamine (NAG), are significantly reduced in inflammatory bowel disease (IBD). This results in deficient GAG content in mucosa, which eventually disrupts the gut wall integrity, provoking abnormal immunological responses. This is characterized by colossal liberation of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukins (IL), and reactive oxygen species provoking colonic inflammation. D-glucosamine (D-GLU) is reported to suppress oxidative stress, and pro-inflammatory cytokines and acts as a starting material for biosynthesis of NAG. The potential of D-GLU and its combination with mesalamine (5-ASA) was investigated in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-instigated IBD in Wistar rats. Standard and test drugs were given orally for five days to separate groups of rats. Colonic inflammation was evaluated by disease activity score rate (DASR), colon/body weight ratio, colon length, diameter, colon pH, histological injury and score. Inflammatory biomarkers IL-1β, TNF-α, along with reduced glutathione (GSH), and malondialdehyde (MDA) were assessed. Combination of D-GLU +5-ASA significantly ameliorated severity of colonic inflammation by lowering DASR (P < 0.001) and colon/body weight ratio (P < 0.001), restored the colonic architecture and suppressed the histopathological score (P < 0.001), along with the absence of major adverse reactions. The combination suppressed the levels of inflammatory markers (P < 0.001) and MDA (P < 0.001) while enhancing GSH level (P < 0.001). In comparison to individual 5-ASA and D-GLU, combination of drugs significantly diminished colitis severity through their combined anti-inflammatory and antioxidant effects by acting on multiple targets simultaneously. The combination holds remarkable potential in the management of IBD.

Efficacy of the use of chondroitin sulphate and glucosamine for the treatment of temporomandibular joint dysfunction: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of chondroitin sulfate (CS) and glucosamine (GS), the most relevant drugs of "Symptomatic Slow Acting Drug for Osteoarthritis" (SYSADOA), in the functional and symptomatic improvement of temporomandibular dysfunction. Although, controversy exists regarding their benefit.

METHODS

An electronic search was conducted to retrieve randomized controlled clinical trials (RCTs). The risk of bias assessment was evaluated using the Cochrane Collaboration's tool. Data were meta-analyzed with a random effect model whenever possible.

RESULTS

Three RCTs were included. Qualitative results showed a decrease in pain, joint noise, and inflammatory biomarkers in synovial fluid and an improvement in maximum mouth opening without significant adverse effects. Meta-analysis showed a significant increase in maximum mouth opening with the use of CS-GS (p = 0.19). No statistically significant differences were found in pain reduction compared to tramadol.

CONCLUSION

CS-GS is effective and safe in the symptomatic and functional improvement of patients with TMD.

Characterization and Evaluation of Antioxidant and Anti-Inflammatory Activities of Flavonoids from the Fruits of Lycium barbarum

The fruits of Lycium barbarum are rich in flavonoids, which may contribute to the health-promoting function of Lycium barbarum. However, the composition of flavonoids in the fruits of Lycium barbarum (LBFs) has received little attention. Thus, the goal of this work was to identify more kinds of flavonoids from fruits of Lycium barbarum by liquid chromatography–mass spectrometry. The potential antioxidant and anti-inflammatory activities of LBFs in vitro were also investigated. Thirteen flavonoid compounds were identified in LBFs, of which daphnetin, 6,7-dihydroxycoumarin, astragalin, taxifolin, eriodictyol, naringenin, and chrysoeriol were identified for the first time in the fruits of Lycium barbarum, which greatly enriched the variety of flavonoids in the fruits of Lycium barbarum. LBFs showed a similar superior antioxidant activity to vitamin C. Furthermore, LBFs exhibited an anti-inflammatory activity by suppressing the production of nitric oxide and pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1β, and interleukin-6, in lipopolysaccharide-treated RAW264.7 macrophage cells. This study demonstrated the potential development of LBFs as functional foods.

LINC01534 Promotes the Aberrant Metabolic Dysfunction and Inflammation in IL-1β-Simulated Osteoarthritic Chondrocytes by Targeting miR-140-5p

OBJECTIVE

Long non-coding RNA 01534 (LINC01534) is highly expressed in the tissues of patients with osteoarthritis (OA). This study investigated the mechanism of LINC01534 on abnormal metabolic dysfunction in OA chondrocytes induced by interleukin-1β (IL-1β).

METHODS

The quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expressions of LINC01534, aggrecan, collagen II, and matrix metalloproteinase (MMPs) in OA cartilage tissue or OA chondrocyte model induced by IL-1β. The expressions of aggrecan and collagen II in the chondrocyte were detected by Western blot. The levels of tumor necrosis factor-α (TNF-α), IL-8, IL-6, MMP-13, MMP-9, MMP-3, and prostaglandin E2 (PGE2) in chondrocyte were determined by enzyme-linked immunosorbernt assay. Bioinformatics, dual luciferin gene reporting, RNA pulldown, and Northern blot were used to determine the interaction between LINC01534 and miR-140-5p.

RESULTS

The results showed that LINC01534 was upregulated in both OA cartilage tissue and OA chondrocyte model. In addition, silencing LINC01534 significantly alleviated the inhibitory effect of IL-1β on expressions of aggrecan and collagen II in chondrocytes, and significantly downregulated the expression of matrix metalloproteinases in IL-1β-induced chondrocytes. Meanwhile, silencing LINC01534 also significantly inhibited the productions of proinflammatory factors NO, PGE2, TNF-α, IL-6, and IL-8 in the IL-1β-induced chondrocytes. Furthermore, miR-140-5p was confirmed to be a direct target of LINC01534. More importantly, inhibition of miR-140-5p significantly reversed the inhibitory effect of silencing LINC01534 on abnormal matrix degradation in the IL-1β-induced chondrocyte model of OA.

CONCLUSION

Therefore, LINC01534 could promote the abnormal matrix degradation and inflammatory response of OA chondrocytes through the targeted binding of miR-140-5p.

Glia and Orofacial Pain: Progress and Future Directions

Orofacial pain is a universal predicament, afflicting millions of individuals worldwide. Research on the molecular mechanisms of orofacial pain has predominately focused on the role of neurons underlying nociception. However, aside from neural mechanisms, non-neuronal cells, such as Schwann cells and satellite ganglion cells in the peripheral nervous system, and microglia and astrocytes in the central nervous system, are important players in both peripheral and central processing of pain in the orofacial region. This review highlights recent molecular and cellular findings of the glia involvement and glia–neuron interactions in four common orofacial pain conditions such as headache, dental pulp injury, temporomandibular joint dysfunction/inflammation, and head and neck cancer. We will discuss the remaining questions and future directions on glial involvement in these four orofacial pain conditions.

In vitro inhibitory effects of glucosamine, chondroitin and diacerein on human hepatic CYP2D6

OBJECTIVES

Glucosamine, chondroitin and diacerein are natural compounds commonly used in treating osteoarthritis. Their concomitant intake may trigger drug-natural product interactions. Cytochrome P450 (CYP) has been implicated in such interactions. Cytochrome P450 2D6 (CYP2D6) is a major hepatic CYP involved in metabolism of 25% of the clinical drugs. This study aimed to investigate the inhibitory effect of these antiarthritic compounds on CYP2D6.

METHODS

CYP2D6 was heterologously expressed in Escherichia coli. CYP2D6-antiarthritic compound interactions were studied using in vitro enzyme kinetics assay and molecular docking.

RESULTS

The high-performance liquid chromatography (HPLC)-based dextromethorphan O-demethylase assay was established as CYP2D6 marker. All glucosamines and chondroitins weakly inhibited CYP2D6 (IC₅₀ values >300 µM). Diacerein exhibited moderate inhibition with IC₅₀ and K _i values of 34.99 and 38.27 µM, respectively. Its major metabolite, rhein displayed stronger inhibition potencies (IC₅₀=26.22 μM and K _i =32.27 μM). Both compounds exhibited mixed-mode of inhibition. In silico molecular dockings further supported data from the in vitro study. From in vitro-in vivo extrapolation, rhein presented an area under the plasma concentration-time curve (AUC) ratio of 1.5, indicating low potential to cause in vivo inhibition.

CONCLUSIONS

Glucosamine, chondroitin and diacerein unlikely cause clinical interaction with the drug substrates of CYP2D6. Rhein, exhibits only low potential to cause in vivo inhibition.

In vitro inhibitory effects of glucosamine, chondroitin and diacerein on human hepatic CYP2D6

OBJECTIVES

Glucosamine, chondroitin and diacerein are natural compounds commonly used in treating osteoarthritis. Their concomitant intake may trigger drug-natural product interactions. Cytochrome P450 (CYP) has been implicated in such interactions. Cytochrome P450 2D6 (CYP2D6) is a major hepatic CYP involved in metabolism of 25% of the clinical drugs. This study aimed to investigate the inhibitory effect of these antiarthritic compounds on CYP2D6.

METHODS

CYP2D6 was heterologously expressed in Escherichia coli. CYP2D6-antiarthritic compound interactions were studied using in vitro enzyme kinetics assay and molecular docking.

RESULTS

The high-performance liquid chromatography (HPLC)-based dextromethorphan O-demethylase assay was established as CYP2D6 marker. All glucosamines and chondroitins weakly inhibited CYP2D6 (IC50 values >300 µM). Diacerein exhibited moderate inhibition with IC50 and K i values of 34.99 and 38.27 µM, respectively. Its major metabolite, rhein displayed stronger inhibition potencies (IC50=26.22 μM and K i =32.27 μM). Both compounds exhibited mixed-mode of inhibition. In silico molecular dockings further supported data from the in vitro study. From in vitro-in vivo extrapolation, rhein presented an area under the plasma concentration-time curve (AUC) ratio of 1.5, indicating low potential to cause in vivo inhibition.

CONCLUSIONS

Glucosamine, chondroitin and diacerein unlikely cause clinical interaction with the drug substrates of CYP2D6. Rhein, exhibits only low potential to cause in vivo inhibition.

Does glucosamine, chondroitin sulfate, and methylsulfonylmethane supplementation improve the outcome of temporomandibular joint osteoarthritis management with arthrocentesis plus intraarticular hyaluronic acid injection. A randomized clinical trial

The purpose of this study was to compare clinical outcomes obtained with the use of glucosamine, chondroitin sulfate, and methylsulfonylmethane (GCM) supplementation after arthrocentesis plus intraarticular hyaluronic acid (HA) injection. A randomized clinical trial was implemented with adult participants with TMJ-OA who were referred to the author's clinic between February 2014 and May 2015. The sample was entirely composed of patients with TMJ-OA who were treated randomly with a one-session arthrocentesis plus intraarticular HA injection only (control group), or an initial one-session arthrocentesis plus intraarticular HA injection followed by 3 months of GCM supplementation (study group). The predictor variable was management (treatment) technique. The outcome variables were visual analog scale evaluations (masticatory efficiency, pain complaint, joint sound) and mandibular mobility (maximal interincisal opening [MIO], and lateral and protrusive motions of the mandible). The outcome variables were recorded preoperatively and 12 months postoperatively. Thirty-one participants were enrolled in the study. Five were lost during follow-up. The final study sample consisted of 26 participants (age 28.35 ± 10.85 y): 14 in the control group (age 28.71 ± 10.94 y); and 12 in the study group (age 27.92 ± 11.20 y). Pain complaints (p < 0.001) and joint sounds (p = 0.030 for the control group; p = 0.023 for the study group) showed statistically significant decreases. Masticatory efficiency (p < 0.001 for the control group; p = 0.040 for the study group) and lateral mandibular motion (p = 0.040 for the control group; p = 0.004 for study group) showed statistically significant increases in both groups, whereas MIO and protrusive mandibular motion showed no significant changes in either group (p > 0.05). After estimating the differences between the follow-up and baseline outcomes, the mean changes in the primary outcome variables (VAS scores, MIO, and mandibular motion) showed no statistically significant differences between the two groups (p > 0.05). Progressions (reparative remodeling) of hard-tissue TMJ structures were observed on CBCT scans of some participants in both groups. These findings suggested that the use of GCM supplementation after arthrocentesis plus intraarticular HA injection produced no additional clinical benefits or improvements for patients with TMJ-OA compared with arthrocentesis plus intraarticular HA injection alone.

Effect of Zhongyi paste on inflammatory pain in mice by regulation of the extracellular regulated protein kinases 1/2-cyclooxygenase-2-prostaglandin E2 pathway

Background

Zhongyi paste is a traditional Chinese medicine herbal paste that is externally applied to reduce inflammation and relieve pain.

Methods

An acute foot swelling inflammation model in C57BL/6J mice was established by carrageenan-induced pathogenesis. Zhongyi paste raised the pain threshold and also reduced the degree of swelling in mice with carrageenan-induced foot swelling.

Results

Analysis indicated that serum tumor necrosis factor-alpha, interleukin-1 beta, and prostaglandin E₂ (PGE₂) cytokine levels and PGE₂ levels in the paw tissue of the mice were decreased by Zhongyi paste treatment. The quantitative polymerase chain reaction and western blot results showed that Zhongyi paste downregulated the mRNA and protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), and cyclooxygenase-2 (COX-2), and also downregulated the mRNA expression of PGE₂. At the same time, the Zhongyi paste exerted a stronger effect as an external drug than that of indomethacin, which is an oral drug, and voltaren, which is an externally applied drug.

Conclusions

Our results indicated that Zhongyi paste is a very effective drug to reduce inflammatory swelling of the foot, and its mechanism of action is related to regulation of the ERK1/2–COX-2–PGE₂ pathway.

Effect of simultaneous application of arthrocentesis and occlusal splint versus splint in management of non-reducing TMJ disc displacement

Background/Purpose

This study aimed to compare the effect of four approaches in the treatment of TMJ disc displacement without reduction (DDwoR).

Materials and methods

Thirty-two patients (40 joints) with mean age 28.025 ± 7.18 (23 female patients and nine male patients) were assigned randomly into four groups (10 joints in each group). Group I, patients were treated by centric splint. Group II, patients were treated by distraction splint. Group III, patients were treated by arthrocentesis and centric splint, while group IV patients were treated by arthrocentesis and distraction splint. The groups were compared in terms of joint function (mouth opening), joint pain through joint palpation, and use of visual analog scale (VAS). These records were taken preoperatively, two weeks, one month, three, and six months postoperatively. Also, the presence of disc recapture was evaluated in all patients on MRI at the end of the treatment period.

Results

Significant improvements in all parameters were recorded in all groups. At two weeks postoperatively, there was a significant improvement in all parameters in group III and group IV than group I and group II, while there was no statistical difference between group III and group IV. Regarding mouth opening and joint palpation, there was a significant improvement in group III than group I and group II. Also, there was a significant improvement in group IV than group II at the subsequent follow-up periods. Regarding VAS, at one and three months postoperatively, there was a significant improvement in group III than other groups.

Conclusion

However, both types of splints provide better results without a statistical difference; the simultaneous application of arthrocentesis and occlusal splint decreases pain and improving the function effectively and more rapidly.

Effect of glucosamine sulphate on the temporomandibular joint of ovariectomised rats

Glycosamine is an amino-monosaccharide present in connective and cartilage tissues that contribute to the maintenance, resistance, flexibility, and elasticity of these tissues. This study aimed to determine the in vivo effects of glucosamine sulphate (GS) on the temporomandibular joint (TMJ) of ovariectomised rats (OVX).Thirty-two rats were distributed into four groups as follows: G1, sham-OVX+saline solution; G2, sham-OVX+glucosamine sulphate (80mg/kg) - oral administration; G3, OVX+saline solution; G4, OVX+glucosamine sulphate (80mg/kg) - oral administration. Animals were treated for seven days. The TMJ was removed and stained with toluidine blue. The thickness of the cartilage layers and cytokines IL-1β, IL-6, and TNF-α levels were determined by histomorphometry and immunoassay, respectively. The administration of GS to OVX females did not change the thickness of condylar cartilage when compared with the other groups (p>0.05). There was an increase in the total cartilage thickness in sham-OVX females. IL-1β and TNF-α levels were significantly lower in sham-OVX females than in OVX females, indicating that ovariectomy acts as potent cytokine inducer. IL-6 levels were significantly higher in sham-OVX females. GS did not affect cytokine production in OVX females (p>0.05). In conclusion, the administration of GS did not affect cytokine levels, but did induce an increase in the total thickness of the TMJ condylar cartilage in sham-OVX rats.

Curcumagalactomannoside/Glucosamine Combination Improved Joint Health Among Osteoarthritic Subjects as Compared to Chondroitin Sulfate/Glucosamine: Double-Blinded, Randomized Controlled Study

Objective: A combination of curcumagalactomannosides (CGM) (400 mg) with glucosamine hydrochloride (GLN) (500 mg) was evaluated against a standard dietary supplement combination chondroitin sulfate (CHN) (415 mg)/GLN (500 mg) for their effectiveness in alleviating the pain and symptoms among osteoarthritic subjects. Design: Randomized, double-blinded and active-controlled study. Settings/Location: The study was conducted in a hospital-based research center in Vadodara, Gujarat, India. Subjects: Eighty subjects (38 males and 42 females), with confirmed osteoarthritis (OA) (Class I-III), were randomized into two parallel groups designated as Group I (CGM-GLN) and Group II (CHN-GLN). Interventions: All the study subjects were supplemented with their corresponding intervention capsules (ether CGM along with GLN or CHN along with GLN), as a single oral dose twice a day, once in the morning 10-15 min before breakfast and again in the evening before dinner, for 84 days. Outcome measures: A validated treadmill uphill walking protocol was used for the study, and the efficiency of supplementation was evaluated using visual analogue scale (VAS) score, Karnofsky Performance Scale (KPS) score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at the baseline, 28th, and 84th day following the treatment. Mechanism of action of CGM-GLN combination was analyzed by measuring the levels of serum inflammatory markers interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and soluble vascular cell adhesion molecule-1 (sVCAM) at the baseline and 84th day. Results: CGM-GLN was found to offer significant beneficial effects to pain, stiffness, and physical function of OA subjects compared with CHN-GLN, which was evident from the improvement in walking performance, VAS score, KPS score, and WOMAC score. The efficiency of CGM-GLN was almost double compared with the CHN-GLN by the end of the study (84th day). A significant reduction of inflammatory serum marker levels was observed among CGM-GLN subjects compared with CHN-GLN subjects. Compared with the baseline, CGM-GLN produced 54.52%, 59.08%, and 22.03% reduction in IL-1β, IL-6, and sVCAM levels, respectively. Whereas CHN-GLN group of subjects expressed only 23.17%, 21.38%, and 6.82% reduction in IL-1β, IL-6, and sVCAM levels, respectively. Conclusions: In conclusion, the present study demonstrated the potential benefits of CGM-GLN supplements in alleviating the symptoms and function of OA subjects compared with the standard CHN-GLN treatment. The augmented efficacy of CGM-GLN combination could be attributed to the enhanced anti-inflammatory effect of CGM.

Reduction of osteoarthritis severity in the temporomandibular joint of rabbits treated with chondroitin sulfate and glucosamine

Osteoarthritis is a degenerative disease that causes substantial changes in joint tissues, such as cartilage degeneration and subchondral bone sclerosis. Chondroitin sulfate and glucosamine are commonly used products for the symptomatic treatment of osteoarthritis. The aim of the present study was to investigate the effects of these products when used as structure-modifying drugs on the progression of osteoarthritis in the rabbit temporomandibular joint. Thirty-six New Zealand rabbits were divided into 3 groups (n = 12/group): control (no disease); osteoarthritis (disease induction); and treatment (disease induction and administration of chondroitin sulfate and glucosamine). Osteoarthritis was induced by intra-articular injection of monosodium iodoacetate. Animals were killed at 30 and 90 days after initiation of therapy. The treatment was effective in reducing disease severity, with late effects and changes in the concentration of glycosaminoglycans in the articular disc. The results indicate that chondroitin sulfate and glucosamine may have a structure-modifying effect on the tissues of rabbit temporomandibular joints altered by osteoarthritis.

The many faces of genetic contributions to temporomandibular joint disorder: An updated review

OBJECTIVES

The aim was to review the literature regarding genetic contributions to temporomandibular joint disorder (TMD) after our 2008 publication.

SETTING AND SAMPLE POPULATION

Literature review.

MATERIAL AND METHODS

PubMed and MEDLINE were used to obtain literature in any language regarding genes and TMD, using the keywords "temporomandibular joint disorder" and "temporomandibular joint dysfunction" for studies published from 2009 to 2017.

RESULTS

In our search, 274 studies were found. We excluded 76 studies from animal models, 22 studies that were in vitro and 120 reports that were not cohort or case-control studies. Of the 274 results, 56 articles were selected for this review. Genes that are suggested to contribute to TMD included the ones related to disc and bone alterations as well as pain sensation.

CONCLUSION

Currently, no evidence of associated genetic variants, which can determine the development of TMD in individuals, could be translated to novel clinical management and public health strategies for patients suffering from TMD.

Analysis of synovial fluid visfatin level in temporomandibular joint disorders

Background: Biochemical analysis of synovial fluid (SF) is an important means of understanding the pathogenesis of temporomandibular disorder (TMD) and confirming diagnoses made using traditional methods. Objective: The aim of this study was to determine whether or not SF visfatin levels can serve as a biochemical marker in the diagnosis of TMD. Method: Sixty samples of SF were obtained from 60 patients with internal derangement (ID) or osteoarthritis (OA). Visfatin in the SF was examined by enzyme-linked immunosorbent assay (ELISA). Result: Visfatin levels showed positive correlations with TMD pain and ID stage and a negative correlation with maximum mouth opening. In addition, Visfatin levels in joints with OA changes in the condyle were significantly higher in comparison to joints with no OA changes. Conclusion: Within the limitations of this study, it can be concluded that visfatin may play a role in the pathogenesis of TMD.

Regulation of inflammation by lipid mediators in oral diseases

Lipid mediators (LM) of inflammation are a class of compounds derived from ω-3 and ω-6 fatty acids that play a wide role in modulating inflammatory responses. Some LM possess pro-inflammatory properties, while others possess proresolving characteristics, and the class switch from pro-inflammatory to proresolving is crucial for tissue homeostasis. In this article, we review the major classes of LM, focusing on their biosynthesis and signaling pathways, and their role in systemic and, especially, oral health and disease. We discuss the detection of these LM in various body fluids, focusing on diagnostic and therapeutic applications. We also present data showing gender-related differences in salivary LM levels in healthy controls, leading to a hypothesis on the etiology of inflammatory diseases, particularly Sjögren's syndrome. We conclude by enumerating open areas of research where further investigation of LM is likely to result in therapeutic and diagnostic advances.