Green tea polyphenol epigallocatechin 3-gallate in arthritis: progress and promise

Pathophysiology, diagnosis, and herbal medicine-based therapeutic implication of rheumatoid arthritis: an overview

Rheumatoid arthritis (RA) stands as an autoimmune disorder characterized by chronic joint inflammation, resulting in profound physiological alterations within the body. Affecting approximately 0.4-1.3% of the global population, this condition poses significant challenges as current therapeutic approaches primarily offer symptomatic relief, with the prospect of complete recovery remaining elusive. This review delves into the contemporary advancements in understanding the pathophysiology, diagnosis, and the therapeutic potential of herbal medicine in managing RA. Notably, early diagnosis during the initial stages emerges as the pivotal determinant for successful recovery post-treatment. Utilizing tools such as Magnetic Resonance Imaging (MRI), anti-citrullinated peptide antibody markers, and radiography proves crucial in pinpointing the diagnosis of RA with precision. Unveiling the intricate pathophysiological mechanisms of RA has paved the way for innovative therapeutic interventions, incorporating plant extracts and isolated phytoconstituents. In the realm of pharmacological therapy for RA, specific disease-modifying antirheumatic drugs have showcased commendable efficacy. However, this conventional approach is not without its drawbacks, as it is often associated with various side effects. The integration of methodological strategies, encompassing both pharmacological and plant-based herbal therapies, presents a promising avenue for achieving substantive recovery. This integrated approach not only addresses the symptoms but also strives to tackle the underlying causes of RA, fostering a more comprehensive and sustainable path towards healing.

Natural products as potential drug treatments for acute promyelocytic leukemia

Acute promyelocytic leukemia (APL), which was once considered one of the deadliest types of leukemia, has become a curable malignancy since the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) as clinical treatments. ATO, which has become the first-line therapeutic agent for APL, is derived from the natural mineral product arsenic, exemplifying an important role of natural products in the treatment of APL. Many other natural products, ranging from small-molecule compounds to herbal extracts, have also demonstrated great potential for the treatment and adjuvant therapy of APL. In this review, we summarize the natural products and representative components that have demonstrated biological activity for the treatment of APL. We also discuss future directions in better exploring their medicinal value, which may provide a reference for subsequent new drug development and combination therapy programs.

Injectable and tissue adhesive EGCG-laden hyaluronic acid hydrogel depot for treating oxidative stress and inflammation

Oxidative stress and inflammation are common pathological mechanisms for the progression of tissue degeneration. Epigallocatechin-3-gallate (EGCG) features antioxidant and anti-inflammatory properties, which is a promising drug for the treatment of tissue degeneration. Herein, we utilize the phenylborate ester reaction of EGCG and phenylboronic acid (PBA) to fabricate an injectable and tissue adhesive EGCG-laden hydrogel depot (EGCG HYPOT), which can achieve anti-inflammatory and antioxidative effects via smart delivery of EGCG. Specifically, the phenylborate ester bonds, formed by EGCG and PBA-modified methacrylated hyaluronic acid (HAMA-PBA), endow EGCG HYPOT injectability, shape adaptation and efficient load of EGCG. After photo-crosslinking, EGCG HYPOT exhibits good mechanical properties, tissue adhesion and sustained acid-responsive release of EGCG. EGCG HYPOT can scavenge oxygen and nitrogen free radicals. Meanwhile, EGCG HYPOT can scavenge intracellular reactive oxygen species (ROS) and suppress the expression of pro-inflammatory factors. EGCG HYPOT may provide a new idea for alleviation of inflammatory disturbance.

Efficacy and safety of dietary polyphenols in rheumatoid arthritis: A systematic review and meta-analysis of 47 randomized controlled trials

OBJECTIVE

To evaluate safety and efficacy of dietary polyphenols in the treatment of rheumatoid arthritis (RA).

METHODS

CNKI, Pubmed, Cochrane library, Embase were searched to collect randomized controlled trials (RCTs) of dietary polyphenols in the treatment of RA. The databases were searched from the time of their establishment to November 8nd, 2022. After 2 reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies, Meta-analysis was performed using RevMan5.4 software.

RESULTS

A total of 49 records (47 RCTs) were finally included, involving 3852 participants and 15 types of dietary polyphenols (Cinnamon extract, Cranberry extract, Crocus sativus L. extract, Curcumin, Garlic extract, Ginger extract, Hesperidin, Olive oil, Pomegranate extract, Puerarin, Quercetin, Resveratrol, Sesamin, Tea polyphenols, Total glucosides of paeony). Pomegranate extract, Resveratrol, Garlic extract, Puerarin, Hesperidin, Ginger extract, Cinnamon extract, Sesamin only involve in 1 RCT. Cranberry extract, Crocus sativus L. extract, Olive oil, Quercetin, Tea polyphenols involve in 2 RCTs. Total glucosides of paeony and Curcumin involve in more than 3 RCTs. These RCTs showed that these dietary polyphenols could improve disease activity score for 28 joints (DAS28), inflammation levels or oxidative stress levels in RA. The addition of dietary polyphenols did not increase adverse events.

CONCLUSION

Dietary polyphenols may improve DAS28, reduce C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and improve oxidative stress, etc. However, more RCTs are needed to verify or modify the efficacy and safety of dietary polyphenols.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42022315645.

The Anti-Inflammatory and Immunomodulatory Activities of Natural Products to Control Autoimmune Inflammation

Inflammation is an integral part of autoimmune diseases, which are caused by dysregulation of the immune system. This dysregulation involves an imbalance between pro-inflammatory versus anti-inflammatory mediators. These mediators include various cytokines and chemokines; defined subsets of T helper/T regulatory cells, M1/M2 macrophages, activating/tolerogenic dendritic cells, and antibody-producing/regulatory B cells. Despite the availability of many anti-inflammatory/immunomodulatory drugs, the severe adverse reactions associated with their long-term use and often their high costs are impediments in effectively controlling the disease process. Accordingly, suitable alternatives are being sought for these conventional drugs. Natural products offer promising adjuncts/alternatives in this regard. The availability of specific compounds isolated from dietary/medicinal plant extracts have permitted rigorous studies on their disease-modulating activities and the mechanisms involved therein. Here, we describe the basic characteristics, mechanisms of action, and preventive/therapeutic applications of 5 well-characterized natural product compounds (Resveratrol, Curcumin, Boswellic acids, Epigallocatechin-3-gallate, and Triptolide). These compounds have been tested extensively in animal models of autoimmunity as well as in limited clinical trials in patients having the corresponding diseases. We have focused our description on predominantly T cell-mediated diseases, such as rheumatoid arthritis, multiple sclerosis, Type 1 diabetes, ulcerative colitis, and psoriasis.

Epigallocatechin-3-Gallate Pretreatment Improves Autologous Adipose-derived Stem Cells Against Rheumatoid Arthritis-induced Neuroinflammation in the Brain of Collagen-induced Rats

Adipose tissue-derived mesenchymal stem cells (ADSC) exert neuroprotective and anti-inflammatory effects. ADSCs are considered potential therapeutics for rheumatoid arthritis (RA), an inflammatory, multisystemic autoimmune disease. Epigallocatechin-3-gallate (EGCG), the major polyphenolic compound in green tea, has strong anti-inflammatory and antioxidant properties. This study aimed to investigate whether EGCG has a synergistic effect on the neuroprotective effects of ADSCs to protect the RA-damaged brain. Wistar rats were classified into four groups: sham, RA, RA + ADSCs (1 × 10⁶ cells per rat), and RA + EGCG (10 µM)-pretreated ADSCs. After 2 months of treatment, the brain tissues from the rats were collected and investigated. The brains of RA rats had higher inflammation and apoptosis. ADSC treatment ameliorated these negative effects significantly; however, the neuroprotective abilities of EGCG-pretreated ADSCs were significantly higher than ADSCs. Furthermore, the RA-induced repression of the PI3K/Akt survival pathway was reactivated by EGCG-pretreated ADSCs. Collectively, this study provides evidence that EGCG synergistically enhances the neuroprotective ability of ADSCs to repress the negative effects of RA on the brain. These findings could help develop new therapeutic strategies against RA or other neurodegenerative diseases after clinical validation in the future.

A Hyperosmolar Saline Solution Fortified with Anti-Inflammatory Components Mitigates Articular Cartilage Pro-Inflammatory and Degradative Responses in an In Vitro Model of Knee Arthroscopy

OBJECTIVE

To evaluate differences in pro-inflammatory and degradative mediator production from osteoarthritic knee articular cartilage explants treated with a hyperosmolar saline solution supplemented with anti-inflammatory components (l-glutamine, ascorbic acid, sodium pyruvate, epigallocatechin gallate [EGCG], and dexamethasone) or normal saline using an in vitro model for knee arthroscopy.

DESIGN

Full-thickness 6 mm articular cartilage explants (n = 12/patient) were created from femoral condyle and tibial plateau samples collected from patients who received knee arthroplasty. One explant half was treated for 3 hours with hyperosmolar saline (600 mOsm/L) supplemented with anti-inflammatory components and the corresponding half with normal saline (308 mOsm/L). Explants were cultured for 3 days and then collected for biomarker analyses. Media biomarker concentrations were normalized to the wet weight of the tissue (mg) and were analyzed by a paired t test with significance set at P < 0.05.

RESULTS

Cartilage was collected from 9 females and 2 males (mean age = 68 years). Concentrations of MCP-1 (P < 0.001), IL-8 (P = 0.03), GRO-α (P = 0.02), MMP-1 (P < 0.001), MMP-2 (P < 0.001), and MMP-3 (P < 0.001) were significantly lower in explant halves treated with the enhanced hyperosmolar solution. When considering only those cartilage explants in the top tercile of tissue metabolism, IL-6 (P = 0.005), IL-8 (P = 0.0001), MCP-1 (P < 0.001), GRO-α (P = 0.0003), MMP-1 (P < 0.001), MMP-2 (P < 0.001), MMP-3 (P < 0.001), and GAG expression (P = 0.0001) was significantly lower in cartilage explant halves treated with the enhanced hyperosmolar solution.

CONCLUSIONS

Treatment of cartilage explants with a hyperosmolar saline arthroscopic irrigation solution supplemented with anti-inflammatory components was associated with significant decreases in inflammatory and degradative mediator production and mitigation of proteoglycan loss.

Targeting immunometabolism by active ingredients derived from traditional Chinese medicines for treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), the most common inflammatory arthropathy word wild, is a systemic autoimmune disease that mainly affects the synovium of joints with a high disability rate. Metabolic mis-regulation has emerged as a fundamental pathogenesis of RA linked to immune cell dysfunction, while targeting immunometabolism provides a new and effective approach to regulate the immune responses and thus alleviate the symptom of RA. Recently, natural active compounds from traditional Chinese medicines (TCMs) have potential therapeutic effects on RA and regulating immunometabolism. In this review, in addition to updating the connection between cellular metabolism and cell function in immune cells of RA, we summarized that the anti-inflammatory mechanisms of the potential natural compounds from TCM by targeting metabolic reprogramming of immune cells, and discusses them as a rich resource for providing the new potential paradigm for the treatment of RA.

Mechanisms and Pharmaceutical Action of Lipid Nanoformulation of Natural Bioactive Compounds as Efficient Delivery Systems in the Therapy of Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease. An objective of the nanomedicine and drug delivery systems field is to design suitable pharmaceutical nanocarriers with controllable properties for drug delivery and site-specific targeting, in order to achieve greater efficacy and minimal toxicity, compared to the conventional drugs. The aim of this review is to present recent data on natural bioactive compounds with anti-inflammatory properties and efficacy in the treatment of OA, their formulation in lipid nanostructured carriers, mainly liposomes, as controlled release systems and the possibility to be intra-articularly (IA) administered. The literature regarding glycosaminoglycans, proteins, polyphenols and their ability to modify the cell response and mechanisms of action in different models of inflammation are reviewed. The advantages and limits of using lipid nanoformulations as drug delivery systems in OA treatment and the suitable route of administration are also discussed. Liposomes containing glycosaminoglycans presented good biocompatibility, lack of immune system activation, targeted delivery of bioactive compounds to the site of action, protection and efficiency of the encapsulated material, and prolonged duration of action, being highly recommended as controlled delivery systems in OA therapy through IA administration. Lipid nanoformulations of polyphenols were tested both in vivo and in vitro models that mimic OA conditions after IA or other routes of administration, recommending their clinical application.

Hyaluronic acid-green tea catechin conjugates as a potential therapeutic agent for rheumatoid arthritis

Fibroblast-like synoviocytes are a key effector cell type involved in the pathogenesis of rheumatoid arthritis. The major green tea catechin, epigallocatechin-3-O-gallate (EGCG), has attracted significant interest for rheumatoid arthritis therapy because of its ability to suppress the proliferation and interleukin-6 secretion of synoviocytes. However, therapeutic efficacy of EGCG has been limited by a lack of target cell specificity. Herein we report hyaluronic acid-EGCG (HA-EGCG) conjugates as an anti-arthritic agent that is capable of targeting fibroblast-like synoviocytes via HA-CD44 interactions. These conjugates exhibited superior anti-proliferative and anti-inflammatory activities compared with EGCG under simulated physiological conditions. Near-infrared fluorescence imaging revealed preferential accumulation of the conjugates at inflamed joints in a collagen-induced arthritis rat model, and their anti-arthritic efficacy was investigated by measuring a change in the edema and histopathological scores. Our findings suggest the potential of HA-EGCG conjugates as an anti-arthritic agent for the treatment of rheumatoid arthritis.

Enhancement of the antibiotic activity by quercetin against Staphylococcus aureus efflux pumps

The objective of this work was to evaluate the inhibitory effect of quercetin on S. aureus Efflux Pumps. The MIC of Quercetin was evaluated through the broth microdilution method, as well as the Efflux Pump inhibition assay through the method of reducing the antibiotic minimum inhibitory concentration as well as that of ethidium bromide. The in silico approach through bioinformatics was performed to demonstrate the molecular mechanism of interaction of the substrate and the binding cavity. The Quercetin inhibition concentration was not clinically relevant. With respect to the reversal of bacterial resistance effect by efflux pump inhibition, this effect was observed with the strains carrying the TetK and NorA pumps. Regarding the interaction between the Quercetin complex and the NorA pump, the extra stability was provided by hydrogen bonds produced by the hydroxyl group.

Nutrition and Rheumatoid Arthritis in the 'Omics' Era

Modern high-throughput 'omics' science tools (including genomics, transcriptomics, proteomics, metabolomics and microbiomics) are currently being applied to nutritional sciences to unravel the fundamental processes of health effects ascribed to particular nutrients in humans and to contribute to more precise nutritional advice. Diet and food components are key environmental factors that interact with the genome, transcriptome, proteome, metabolome and the microbiota, and this life-long interplay defines health and diseases state of the individual. Rheumatoid arthritis (RA) is a chronic autoimmune disease featured by a systemic immune-inflammatory response, in genetically susceptible individuals exposed to environmental triggers, including diet. In recent years increasing evidences suggested that nutritional factors and gut microbiome have a central role in RA risk and progression. The aim of this review is to summarize the main and most recent applications of 'omics' technologies in human nutrition and in RA research, examining the possible influences of some nutrients and nutritional patterns on RA pathogenesis, following a nutrigenomics approach. The opportunities and challenges of novel 'omics technologies' in the exploration of new avenues in RA and nutritional research to prevent and manage RA will be also discussed.

Amelioration of oxidative and inflammatory changes by Peganum harmala seeds in experimental arthritis

Background

The present study was designed to investigate the therapeutic effects against oxidative stress and alleviative effects of Peganum harmala seeds (PH) in rats with Complete Freund’s Adjuvant (CFA) induced arthritis.

Methods

The extract was evaluated for its phytoconstituents, antiarthritic and antioxidant properties. The action of chloroform (PHC) and ethanolic (PHE) extracts of PH was evaluated in adult Lewis rats (150-200 g).with CFA induced arthritis. Arthritic rats received PH extracts 100 mg/kg orally for 28 consecutive days (Prophylactic treatment) and from 14th day of CFA injection (Therapeutic treatment).

Results

PHE significantly suppressed the arthritis severity in rats than PHC in 28 days. All complications shown significant reduction (p< 0.05) in arthritic rats including paw volume (63.09%), body weight loss, decreased locomotor activity, erythrocyte sedimentation rate and synovial/hepatic tissues lipid peroxidation and increase in cellular antioxidants superoxide dismutase (U/mg) activities and hemoglobin counts. The results showed the presence of alkaloids and flavonoids in PHE. Histology and radiographic analysis of arthritic ankle joints indicated abnormal changes. Marked reduction in inflammation and arthritic changes were observed after treatment with PHE.

Conclusion

Therefore, the investigation suggests that PHE at 100 mg/kg will be useful in the management of rheumatoid arthritis complications which may possibly be due to boosting the intracellular antioxidant defense.

Marine Collagen Hydrolysates Downregulate the Synthesis of Pro-Catabolic and Pro-Inflammatory Markers of Osteoarthritis and Favor Collagen Production and Metabolic Activity in Equine Articular Chondrocyte Organoids

Articular cartilage experiences mechanical constraints leading to chondral defects that inevitably evolve into osteoarthritis (OA), because cartilage has poor intrinsic repair capacity. Although OA is an incurable degenerative disease, several dietary supplements may help improve OA outcomes. In this study, we investigated the effects of Dielen^® hydrolyzed fish collagens from skin (Promerim^®30 and Promerim^®60) and cartilage (Promerim^®40) to analyze the phenotype and metabolism of equine articular chondrocytes (eACs) cultured as organoids. Here, our findings demonstrated the absence of cytotoxicity and the beneficial effect of Promerim^® hydrolysates on eAC metabolic activity under physioxia; further, Promerim^®30 also delayed eAC senescence. To assess the effect of Promerim^® in a cartilage-like tissue, eACs were cultured as organoids under hypoxia with or without BMP-2 and/or IL-1β. In some instances, alone or in the presence of IL-1β, Promerim^®30 and Promerim^®40 increased protein synthesis of collagen types I and II, while decreasing transcript levels of proteases involved in OA pathogenesis, namely Htra1, and the metalloproteinases Mmp1-3, Adamts5, and Cox2. Both Promerim^® hydrolysates also decreased Htra1 protein amounts, particularly in inflammatory conditions. The effect of Promerim^® was enhanced under inflammatory conditions, possibly due to a decrease in the synthesis of inflammation-associated molecules. Finally, Promerim^® favored in vitro repair in a scratch wound assay through an increase in cell proliferation or migration. Altogether, these data show that Promerim^®30 and 40 hold promise as dietary supplements to relieve OA symptoms in patients and to delay OA progression.

Amelioration of pulmonary aflatoxicosis by green tea extract: An in vivo study

Aflatoxins (AFB₁) are mycotoxins known to be associated with human and animal diseases. The lung is a at risk from AFB₁exposure either via inhalation or circulation. Green tea consumption is increasing over time due to widespread popularity as antioxidants, anti-inflammatory, and cytoprotective agents. Therefore, we attempted to study the lung toxicity caused by AFB₁ and the possible ameliorating effect of green tea extract. Forty adult male albino rats were divided into five groups; Group I: Untreated control group, Group II (vehicle): Each rat received 1 ml of olive oil, Group III (GTE): Each rat received Camellia sinensis, green tea extract (30 mg/kg/day), Group IV(AFB₁): Each rat received (50 μg/kg/day of AFB₁). Group V (AFB₁+ GTE): Each rat received the same previously mentioned doses of AFB1 in addition to GTE concomitantly. All treatments were orally gavaged for 8 weeks then rats were sacrificed. Serum levels of pro-inflammatory (IL-1β, TNF-α, IL-6) and anti-inflammatory (IL-10) cytokines were measured, lung tissues' oxidative stress indices were also measured in addition to the histopathological study which was performed by using hematoxylin & eosin and Masson trichrome stains. Morphometric and statistical analyses were also performed. Oral gavage of AFB₁ resulted in significant histopathological changes in the lung tissues, in the form of variable degrees of congestion, hemorrhage, interstitial inflammation with infiltration by chronic inflammatory cells, interstitial fibrosis, bronchitis, vasculitis and fibrous thickening of arterial walls. Inflammation was evident by elevated levels of pro-inflammatory cytokines and a declined level of anti-inflammatory cytokines. Also, oxidative stress was evident by increased levels of Malondialdehyde (MDA), Myeloperoxidase (MPO), and decreased levels of total glutathione (tGSH) and Catalase (CAT). The histopathological changes, inflammatory cytokines, and oxidative stress markers were significantly decreased during concomitant administration of green tea extract in (AFB₁+ GTE) group. Aflatoxin B₁ has deleterious effects on the lung tissue that could be minimized by concomitant administration of Green tea extract owing to its anti-inflammatory, antioxidant, and protective properties.

Current and novel therapeutic targets in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a multifactorial disease characterized by synovitis, cartilage destruction, bone erosion, and periarticular decalcification, finally results in impairment of joint function. Both genetic and environmental factors are risk factors in the development of RA. Unwanted side effects accompany most of the current treatment strategies, and around 20-40% of patients with RA do not clinically benefit from these treatments. The unmet need for new treatment options for RA has prompted research in the development of novel agents acting through physiologically and pharmacologically relevant targets. Here we discuss in detail three critical pathways, Janus kinase/signal transducer and activator of transcription (JAK/STAT), Th17, and hypoxia-inducible factor (HIF), and their roles as unique therapeutic targets in the field of RA. Some of the less developed but potential targets like nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome and histone deacetylase 1 (HDAC1) are also discussed.

Molecular mechanisms of action of epigallocatechin gallate in cancer: Recent trends and advancement

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is an ester of epigallocatechin and gallic acid. EGCG, abundantly found in tea, is a polyphenolic flavonoid that has the potential to affect human health and disease. EGCG interacts with various recognized cellular targets and inhibits cancer cell proliferation by inducing apoptosis and cell cycle arrest. In addition, scientific evidence has illustrated the promising role of EGCG in inhibiting tumor cell metastasis and angiogenesis. It has also been found that EGCG may reverse drug resistance of cancer cells and could be a promising candidate for synergism studies. The prospective importance of EGCG in cancer treatment is owed to its natural origin, safety, and low cost which presents it as an attractive target for further development of novel cancer therapeutics. A major challenge with EGCG is its low bioavailability which is being targeted for improvement by encapsulating EGCG in nano-sized vehicles for further delivery. However, there are major limitations of the studies on EGCG, including study design, experimental bias, and inconsistent results and reproducibility among different study cohorts. Additionally, it is important to identify specific EGCG pharmacological targets in the tumor-specific signaling pathways for development of novel combined therapeutic treatments with EGCG. The present review highlights the ongoing development to identify cellular and molecular targets of EGCG in cancer. Furthermore, the role of nanotechnology-mediated EGCG combinations and delivery systems will also be discussed.

Cladophora glomerata methanolic extract promotes chondrogenic gene expression and cartilage phenotype differentiation in equine adipose-derived mesenchymal stromal stem cells affected by metabolic syndrome

BACKGROUND

Chondrogenesis represents a highly dynamic cellular process that leads to the establishment of various types of cartilage. However, when stress-related injuries occur, a rapid and efficient regeneration of the tissues is necessary to maintain cartilage integrity. Mesenchymal stem cells (MSCs) are known to exhibit high capacity for self-renewal and pluripotency effects, and thus play a pivotal role in the repair and regeneration of damaged cartilage. On the other hand, the influence of certain pathological conditions such as metabolic disorders on MSCs can seriously impair their regenerative properties and thus reduce their therapeutic potential.

OBJECTIVES

In this investigation, we attempted to improve and potentiate the in vitro chondrogenic ability of adipose-derived mesenchymal stromal stem cells (ASCs) isolated from horses suffering from metabolic syndrome.

METHODS

Cultured cells in chondrogenic-inductive medium supplemented with Cladophora glomerata methanolic extract were experimented for expression of the main genes and microRNAs involved in the differentiation process using RT-PCR, for their morphological changes through confocal and scanning electron microscopy and for their physiological homeostasis.

RESULTS

The different added concentrations of C. glomerata extract to the basic chondrogenic inductive culture medium promoted the proliferation of equine metabolic syndrome ASCs (ASCs_EMS) and resulted in chondrogenic phenotype differentiation and higher mRNA expression of collagen type II, aggrecan, cartilage oligomeric matrix protein, and Sox9 among others. The results reveal an obvious inhibitory effect of hypertrophy and a strong repression of miR-145-5p, miR-146-3p, and miR-34a and miR-449a largely involved in cartilage degradation. Treated cells additionally exhibited significant reduced apoptosis and oxidative stress, as well as promoted viability and mitochondrial potentiation.

CONCLUSION

Chondrogenesis in EqASCs_EMS was found to be prominent after chondrogenic induction in conditions containing C. glomerata extract, suggesting that the macroalgae could be considered for the enhancement of ASC cultures and their reparative properties.

Pathophysiological mechanisms of diabetic cardiomyopathy and the therapeutic potential of epigallocatechin-3-gallate

Cardiovascular complications are considered one of the leading causes of morbidity and mortality among diabetic patients. Diabetic cardiomyopathy (DCM) is a type of cardiovascular damage presents in diabetic patients independent of the coexistence of ischemic heart disease or hypertension. It is characterized by impaired diastolic relaxation time, myocardial dilatation and hypertrophy and reduced systolic and diastolic functions of the left ventricle. Molecular mechanisms underlying these pathological changes in the diabetic heart are most likely multifactorial and include, but not limited to, oxidative/nitrosative stress, increased advanced glycation end products, mitochondrial dysfunction, inflammation and cell death. The aim of this review is to address the major molecular mechanisms implicated in the pathogenesis of DCM. In addition, this review provides studies conducted to determine the pharmacological effects of (-)-epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, focusing on its therapeutic potential against the processes involved in the pathogenesis and progression of DCM. EGCG has been shown to exert several potential therapeutic properties both in vitro and in vivo. Given its therapeutic potential, EGCG might be a promising drug candidate to decrease the morbidity and mortality associated with DCM and other diabetes complications.

The role of diet in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic connective tissue disease which develops in the course of an autoimmune inflammatory process triggered by environmental factors in a genetically predisposed person. One of the environmental factors is the diet. RA patients' adherence to a healthy diet remains low, despite plentiful data confirming positive effects of some foods, e.g. fish rich in n-3 polyunsaturated fatty acids (PUFAs), as well as the negative influence of unhealthy eating patterns, such as high consumption of fats and sugars, on RA incidence, activity and treatment response. In this review, we present current knowledge on the role of diet in rheumatoid arthritis, including dietary factors' preventive/promoting influence on RA development, as well as their impact on RA activity. We hope this article will aid and encourage clinicians to recommend a relevant dietary intervention to their RA patients.

Polyphenol uses in biomaterials engineering

Polyphenols are micronutrients obtained from diet that have been suggested to play an important role in health. The health benefits of polyphenols and their protective effects in food systems as antioxidant compounds are well known and have been extensively investigated. However, their functional roles as a "processing cofactor" in tissue engineering applications are less widely known. This review focuses on the functionality of polyphenols and their application in biomaterials. Polyphenols have been used to stabilize collagen and to improve its resistance to degradation in biological systems. Therefore, they have been proposed to improve the performance of biomedical devices used in cardiovascular systems by improving the mechanical properties of grafted heart valves, enhancing microcirculation through the relaxation of the arterial walls and improving the capillary blood flow and pressure resistance. Polyphenols have been found to stimulate bone formation, mineralization, as well as the proliferation, differentiation, and the survival of osteoblasts. These effects are brought about by the stimulatory effect of polyphenols on osteoblast cells and their protective effect against oxidative stress and inflammatory cytokines. In addition, polyphenols inhibit the differentiation of the osteoclast cells. Collectively, these actions lead to promote bone formation and to reduce bone resorption, respectively. Moreover, polyphenols can increase the cross-linking of dentine and hence its mechanical stability. Overall, polyphenols provide interesting properties that will stimulate further research in the bioengineering field.

Nrf2 as a therapeutic target for rheumatic diseases

Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master regulator of cellular protective processes. Rheumatic diseases are chronic conditions characterized by inflammation, pain, tissue damage and limitations in function. Main examples are rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis and osteoporosis. Their high prevalence constitutes a major health problem with an important social and economic impact. A wide range of evidence indicates that Nrf2 may control different mechanisms involved in the physiopathology of rheumatic conditions. Therefore, the appropriate expression and balance of Nrf2 is necessary for regulation of oxidative stress, inflammation, immune responses, and cartilage and bone metabolism. Numerous studies have demonstrated that Nrf2 deficiency aggravates the disease in experimental models while Nrf2 activation results in immunoregulatory and anti-inflammatory effects. These reports reinforce the increasing interest in the pharmacologic regulation of Nrf2 and its potential applications. Nevertheless, a majority of Nrf2 inducers are electrophilic molecules which may present off-target effects. In recent years, novel strategies have been sought to modulate the Nrf2 pathway which has emerged as a therapeutic target in rheumatic conditions.

Nutraceuticals and osteoarthritis pain

Arthritis is a chronic disease of joints. It is highly prevalent, particularly in the elderly, and is commonly associated with pain that interferes with quality of life. Because of its chronic nature, pharmacological approaches to pain relief and joint repair must be safe for long term use, a quality many current therapies lack. Nutraceuticals refer to compounds or materials that can function as nutrition and exert a potential therapeutic effect, including the relief of pain, such as pain related to arthritis, of which osteoarthritis (OA) is the most common form. Of interest, nutraceuticals have recently been shown to have potential in relieving OA pain in human clinical trials. Emerging evidence indicates nutraceuticals may represent promising alternatives for the relief of OA pain. In this paper, we will overview OA pain and the use of nutraceuticals in OA pain management, focusing on those that have been evaluated by clinical trials. Furthermore, we discuss the biologic and pharmacologic actions underlying the nutraceutical effects on pain relief based on the potential active ingredients identified from traditional nutraceuticals in OA pain management and their potential for drug development. The review concludes by sharing our viewpoints that future studies should prioritize elucidating the mechanisms of action of nutraceuticals in OA and developing nutraceuticals that not only relieve OA pain, but also mitigate OA pathology.

Transforming growth factor β activated kinase 1: a potential therapeutic target for rheumatic diseases

Pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α are central regulators of autoinflammatory diseases. While targeting these cytokines has proven to be a successful clinical strategy, the long-term challenges such as drug resistance, lack of efficacy and poor clinical outcomes in some patients are some of the limitations faced by these therapies. This has ignited strategies to reduce inflammation by potentially targeting a variety of molecules, including cell surface receptors, signalling proteins and/or transcription factors to minimize cytokine-induced inflammation and tissue injury. In this regard, transforming growth factor β activated kinase 1 (TAK1) is activated in the inflammatory signal transduction pathways in response to IL-1β, TNF-α or toll-like receptor stimulation. Because of its ideal position upstream of mitogen-activated protein kinases and the IκB kinase complex in signalling cascades, targeting TAK1 may be an attractive strategy for treating diseases characterized by chronic inflammation. Here, we discuss the emerging role of TAK1 in mediating the IL-1β, TNF-α and toll-like receptor mediated inflammatory responses in diseases such as RA, OA, gout and SS. We also review evidence suggesting that TAK1 inhibition may have potential therapeutic value. Finally, we focus on the current status of the development of TAK1 inhibitors and suggest further opportunities for testing TAK1 inhibitors in rheumatic diseases.

Molecular insights into the differences in anti-inflammatory activities of green tea catechins on IL-1β signaling in rheumatoid arthritis synovial fibroblasts

In this study, we found that catechins found in green tea (EGCG, EGC, and EC) differentially interfere with the IL-1β signaling pathway which regulates the expression of pro-inflammatory mediators (IL-6 and IL-8) and Cox-2 in primary human rheumatoid arthritis synovial fibroblasts (RASFs). EGCG and EGC inhibited IL-6, IL-8, and MMP-2 production and selectively inhibited Cox-2 expression. EC did not exhibit any inhibitory effects. When we looked at the expression of key signaling proteins in the IL-1β signaling pathway, we found all the tested catechins could inhibit TAK-1 activity. Therefore, the consumption of green tea offers an overall anti-inflammatory effect. Molecular docking analysis confirms that EGCG, EGC, and EC all occupy the active site of the TAK1 kinase domain. However, EGCG occupies the majority of the TAK1 active site. In addition to TAK1 inhibition, EGCG can also inhibit P38 and nuclear NF-κB expression whereas EC and EGC were not effective inhibitors. Our findings suggest one of the main health benefits associated with the consumption of green tea are due to the activity of EGCG and EGC which are both present at higher amounts. Although EGCG is the most effective catechin at inhibiting downstream inflammatory signaling, its effectiveness could be hindered by the presence of EC. Therefore, varying EC content in green tea may reduce the anti-inflammatory effects of other potential catechins in green tea.

Insights into the Action Mechanisms of Traditional Chinese Medicine in Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by articular cartilage destruction, synovial inflammation, and osteophyte formation. No effective treatments are available. The current pharmacological medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesics, accompanied by possible adverse effects, might ameliorate OA symptoms. But they do not arrest the progression of OA. Traditional Chinese medicine (TCM) provides medical value by modification of disease and symptoms in OA. Valuable work on exploring TCM merits for OA patients has been investigated using modern technologies, although the complicated interacting network among the numerous components indicates the uncertainty of target specification. This review will provide an overview of the action mechanism of TCM in the last 5 years, discussing the TCM activities of anti-inflammation, antiapoptosis, antioxidation, anticatabolism, and proliferation in OA. TCM is a proposed medical option for OA treatment.

Effect of nobiletin on the MAPK/NF-κB signaling pathway in the synovial membrane of rats with arthritis induced by collagen

Nobiletin (5,6,7,8,3′,4′-hexamethoxyflavone) is a natural compound in the fruit peel of citrus fruit in the Rutaceae family.

Nutraceutical Supplements in the Management and Prevention of Osteoarthritis

Nutraceuticals are dietary compounds which have a role in the balance of anabolic and catabolic signals in joints. Their regulatory function on homeostasis of cartilage metabolism nutraceuticals is increasingly considered for the management and, above all, the prevention of osteoarthritis (OA). OA is a degenerative disease characterized by cartilage and synovium inflammation that can cause joint stiffness, swelling, pain, and loss of mobility. It is a multifactorial disease and, due to the great percentage of people suffering from it and the general increase in life expectancy, OA is considered as one of the most significant causes of disability in the world. OA impairs the structural integrity of articular cartilage that greatly depends on a balance between the anabolic and catabolic processes which occur in chondrocytes and synovial fluid of the joints, therefore the integration with nutraceutical compounds in diet increases the treatment options for patients with established OA beyond traditional rehabilitation, medications, and surgical strategies. In our review, with respect to the current literature, we highlight some of many existing nutraceutical compounds that could be used as integrators in a daily diet thanks to their easy availability, such as in olive oil, fish oil, and botanical extracts used as non-pharmacologic treatment.

Phytoconstituents as pharmacotherapeutics in rheumatoid arthritis: challenges and scope of nano/submicromedicine in its effective delivery

Objectives

The present review explores the therapeutic application of herbals in rheumatoid arthritis (RA) therapy, and how nano/submicromedicine can be fit in the scope of its therapeutic delivery in RA has been addressed.

Key findings

Incorporation of bioactive such as polyphenols, thymoquinone, resveratrol, hesperidin, curcumin, celastrol and gambogic acid in a dose-dependent manner showed quite high efficacy for the treatment of RA. It can be attributed to their targeting ability against various inflammatory mediators including nitric oxide (NO), cytokines, chemokines, adhesion molecules, NF-kβ, lipoxygenase (LOXs) and arachidonic acid (AA). Despite the presence of significant merits, the use of these bioactives has several demerits such as poor bioavailability as a function of low aqueous solubility and higher first-pass metabolism upon oral administration. The impact of nano/submicromedicine in the delivery of these bioactives against RA has gained wider attention owing to bioavailability enhancement, higher stability and better efficacy.

Conclusion

Phytoconstituents possess immense potential in RA pharmacotherapy, but the obstacles for their effective delivery can be overcome using nano/submicrocarrier-based drug delivery technologies, which maximize the efficacy of these herbal antirheumatic drugs without any systemic adverse effects.

Epigallocatechin-3-O-gallate up-regulates microRNA-199a-3p expression by down-regulating the expression of cyclooxygenase-2 in stimulated human osteoarthritis chondrocytes

Osteoarthritis (OA) is a most common form of arthritis worldwide leading to significant disability. MicroRNAs (miRNAs) are non‐coding RNAs involved in various aspects of cartilage development, homoeostasis and pathology. Several miRNAs have been identified which have shown to regulate expression of target genes relevant to OA pathogenesis such as matrix metalloproteinase (MMP)‐13, cyclooxygenase (COX)‐2, etc. Epigallocatechin‐3‐O‐gallate (EGCG), the most abundant and active polyphenol in green tea, has been reported to have anti‐arthritic effects, however, the role of EGCG in the regulation of miRNAs has not been investigated in OA. Here, we showed that EGCG inhibits COX‐2 mRNA/protein expression or prostaglandin E₂ (PGE₂) production via up‐regulating microRNA hsa‐miR‐199a‐3p expression in interleukin (IL)‐1β‐stimulated human OA chondrocytes. This negative co‐regulation of hsa‐miR‐199a‐3p and COX‐2 by EGCG was confirmed by transfection of OA chondrocytes with anti‐miR‐199a‐3p. Transfection of OA chondrocytes with anti‐miR‐199a‐3p significantly enhanced COX‐2 expression and PGE₂ production (P < 0.001), while EGCG treatment significantly inhibited anti‐miR‐199a‐3p transfection‐induced COX‐2 expression or PGE₂ production in a dose‐dependent manner. These results were further re‐validated by co‐treatment of these transfection OA chondrocytes with IL‐1β and EGCG. EGCG treatment consistently up‐regulated the IL‐1β‐decreased hsa‐miR‐199a‐3p expression (P < 0.05) and significantly inhibited the IL‐1β‐induced COX‐2 expression/PGE₂ production (P < 0.05) in OA chondrocytes transfected with anti‐hsa‐miR‐199a‐3p. Taken together, these results clearly indicate that EGCG inhibits COX‐2 expression/PGE₂ production via up‐regulation of hsa‐miR‐199a‐3p expression. These novel pharmacological actions of EGCG on IL‐1β‐stimulated human OA chondrocytes provide new suggestions that EGCG or EGCG‐derived compounds inhibit cartilage breakdown or pain by up‐regulating the expression of microRNAs in human chondrocytes.

Long-Term Effects of (-)-Epigallocatechin Gallate (EGCG) on Pristane-Induced Arthritis (PIA) in Female Dark Agouti Rats

Rheumatoid arthritis (RA)--a widespread chronic inflammatory disease in industrialized countries--is characterized by a persistent and progressive joint destruction. The chronic pro-inflammatory state results from a mutual activation of the innate and the adaptive immune system, while the exact pathogenesis mechanism is still under discussion. New data suggest a role of the innate immune system and especially polymorphonuclear granulocytes (PMNs, neutrophils) not only during onset and the destructive phase of RA but also at the chronification of the disease. Thereby the enzymatic activity of myeloperoxidase (MPO), a peroxidase strongly abundant in neutrophils, may be important: While its peroxidase activity is known to contribute to cartilage destruction at later stages of RA the almost MPO-specific oxidant hypochlorous acid (HOCl) is also discussed for certain anti-inflammatory effects. In this study we used pristane-induced arthritis (PIA) in Dark Agouti rats as a model for the chronic course of RA in man. We were able to shown that a specific detection of the HOCl-producing MPO activity provides a sensitive new marker to evaluate the actual systemic inflammatory status which is only partially detectable by the evaluation of clinical symptoms (joint swelling and redness measurements). Moreover, we evaluated the long-term pharmacological effect of the well-known anti-inflammatory flavonoid epigallocatechin gallate (EGCG). Thereby only upon early and continuous oral application of this polyphenol the arthritic symptoms were considerably diminished both in the acute and in the chronic phase of the disease. The obtained results were comparable to the treatment control (application of methotrexate, MTX). As revealed by stopped-flow kinetic measurements, EGCG may regenerate the HOCl-production of MPO which is known to be impaired at chronic inflammatory diseases like RA. It can be speculated that this MPO activity-promoting effect of EGCG may contribute to the pharmacological mode of action of this polyphenol.

Repeated dose studies with pure Epigallocatechin-3-gallate demonstrated dose and route dependant hepatotoxicity with associated dyslipidemia

EGCG (Epigallocatechin-3-gallate) is the major active principle catechin found in green tea. Skepticism regarding the safety of consuming EGCG is gaining attention, despite the fact that it is widely being touted for its potential health benefits, including anti-cancer properties. The lack of scientific data on safe dose levels of pure EGCG is of concern, while EGCG has been commonly studied as a component of GTE (Green tea extract) and not as a single active constituent. This study has been carried out to estimate the maximum tolerated non-toxic dose of pure EGCG and to identify the treatment related risk factors. In a fourteen day consecutive treatment, two different administration modalities were compared, offering an improved [i.p (intraperitoneal)] and limited [p.o (oral)] bioavailability. A trend of dose and route dependant hepatotoxicity was observed particularly with i.p treatment and EGCG increased serum lipid profile in parallel to hepatotoxicity. Fourteen day tolerable dose of EGCG was established as 21.1 mg/kg for i.p and 67.8 mg/kg for p.o. We also observed that, EGCG induced effects by both treatment routes are reversible, subsequent to an observation period for further fourteen days after cessation of treatment. It was demonstrated that the severity of EGCG induced toxicity appears to be a function of dose, route of administration and period of treatment.

Green Tea Epigallocatechin-3-Gallate Suppresses Autoimmune Arthritis Through Indoleamine-2,3-Dioxygenase Expressing Dendritic Cells and the Nuclear Factor, Erythroid 2-Like 2 Antioxidant Pathway

Background

The activity of one of the major catechins in Green Tea, the polyphenol (−)-epigallocatechin-3-gallate (EGCG), has been shown to have a variety of health benefits. Recent studies suggest that EGCG can modulate both the innate and adaptive arms of the immune system. The goal of the current studies was to examine the immunomodulatory effects and mechanisms of action of EGCG on experimental arthritis in mice.

Methods

EGCG (10 mg/kg) was administered by oral gavage after CIA induction, while control mice were administered phosphate buffered saline (PBS). Disease mechanisms were studied in both groups of mice. Phenotypes were examined using repeated measure analysis of variance (ANOVA) and data from in vitro and ex vivo experiments were analyzed for significance using the Mann-Whitney U test.

Results

EGCG treatment ameliorated clinical symptoms and reduced histological scores in arthritic mice. Serum type-II collagen-specific immunoglobulin (Ig) IgG2a antibodies were significantly lower in EGCG-fed mice compared to PBS-treated mice. EGCG significantly suppressed T cell proliferation and relative frequencies of CD4 T cells, CD8 T cells and B cell subsets including marginal zone B cells, T1 and T2 transitional B cells, while increasing the frequency of CD4⁺ Foxp3⁺ regulatory T cells (Tregs) and indoleamine‐2,3‐dioxygenase (IDO) expression by CD11b⁺ dendritic cells (DC). Splenic CD11b⁺ DC from EGCG fed mice induced an increased frequency of Tregs via an IDO-dependent mechanism in in vitro cultures. Importantly, joint homogenates from EGCG-fed mice exhibited significantly increased levels of Nuclear Factor, Erythroid 2-Like 2 (Nrf-2) and Heme oxygenase-1 (HO-1) compared with PBS-fed mice.

Conclusions

This is the first report of upregulation of the Nrf-2 antioxidant pathway in EGCG-mediated immunoregulation. EGCG ameliorated experimental arthritis in mice by eliciting IDO-producing DCs, increasing frequencies of T regs and inducing the activation of the Nrf-2 antioxidant pathway. It remains to be established whether EGCG is useful for the prevention and treatment of rheumatoid arthritis and other inflammatory disorders.

Nanomedicine in the ROS-mediated pathophysiology: Applications and clinical advances

Reactive oxygen species (ROS) are important in regulating normal cell physiological functions, but when produced in excess lead to the augmented pathogenesis of various diseases. Among these, ischemia reperfusion injury, Alzheimer's disease and rheumatoid arthritis are particularly important. Since ROS can be counteracted by a variety of antioxidants, natural and synthetic antioxidants have been developed. However, due to the ubiquitous production of ROS in living systems, poor in vivo efficiency of these agents and lack of target specificity, the current clinical modalities to treat oxidative stress damage are limited. Advances in the developing field of nanomedicine have yielded nanoparticles that can prolong antioxidant activity, and target specificity of these agents. This article reviews recent advances in antioxidant nanoparticles and their applications to manage oxidative stress-mediated diseases.

FROM THE CLINICAL EDITOR

Production of reactive oxygen species (ROS) is a purely physiological process in many disease conditions. However, excessive and uncontrolled production will lead to oxidative stress and further tissue damage. Advances in nanomedicine have provided many novel strategies to try to combat and counteract ROS. In this review article, the authors comprehensively highlighted the current status and future developments in using nanotechnology for providing novel therapeutic options in this field.

Anti-arthritic agents: progress and potential

Osteoarthritis and rheumatoid arthritis are the two most common types of arthritis. Cartilage breakdown is a key feature of both diseases which contributes to the pain and joint deformity experienced by patients. Therefore, anti-arthritis drugs are of great importance. The aim of this review is to present recent progress in studies of various agents against osteoarthritis and rheumatoid arthritis. The structures and activities of anti-arthritic agents, which used in medical practice or are in development, are presented and discussed. The effects and mechanisms of action of opioids, glucocorticoids, non-steroidal anti-inflammatory drugs, disease-modifying anti-rheumatic drugs, natural products derived from plants, nutraceuticals, and a number of new and perspective agents are considered. Various perspective targets for the treatment of osteoarthritis and rheumatoid arthritis are also discussed. Trials of good quality are needed to draw solid conclusions regarding efficacy of many of the studied agents. Unfortunately, to date, there is no pharmacologic agent proven to prevent the progression of both diseases, and there is an urgent need for further development of better anti-arthritic agents.

Anti-inflammatory activity of green versus black tea aqueous extract in a rat model of human rheumatoid arthritis

AIM

Recently, there has been an increasing interest in tea (Camellia sinensis) as a protective agent against inflammatory diseases. Here, we evaluated/compared the anti-inflammatory activity of two different doses (0.5 and 1.0 g/kg body weight) of green tea aqueous extract (GTE, rich in catechins) and black tea aqueous extract (BTE, rich in theaflavins and thearubigins) in rat adjuvant-induced arthritis (AIA).

METHODS

Adjuvant-induced arthritis rat model received orally/daily distilled water as vehicle, indomethacin (1.0 mg/kg body weight; a non-steroidal/anti-inflammatory drug), or tea aqueous extracts (for 28 or 14 consecutive days starting from day 0 or 14 of arthritis induction, respectively).

RESULTS

The present study showed that only the high dose of GTE (from day 0) significantly alleviated (P < 0.05-0.001) all complications shown in arthritic rats, including synovial joint inflammation, elevation in erythrocyte sedimentation rate, blood leukocytosis (due to lymphocytosis and neutrocytosis), and changes in weight/cellularity of lymphoid organs. The anti-arthritic activity of the high dose of GTE (from day 0) was comparable (P > 0.05) with that of indomethacin (12.9-53.8 vs. 9.5-48.4%, respectively) and mediated by significantly decreasing and down-regulating (P < 0.001) the systemic production of pro-inflammatory cytokines and the expression of chemokine receptor-5 in synovial tissues, respectively. Moreover, the anti-arthritic activity of tea aqueous extracts was in the following order: high dose of GTE > low dose of GTE ≥ high dose of BTE > low dose of BTE.

CONCLUSION

The present study proved the anti-inflammatory activity of GTE over BTE and equal to that of indomethacin in AIA rat model.

Curcuminoids extract, hydrolyzed collagen and green tea extract synergically inhibit inflammatory and catabolic mediator's synthesis by normal bovine and osteoarthritic human chondrocytes in monolayer

The main objective of this study was to assess the in vitro effects of curcuminoids extract, hydrolyzed collagen and green tea extract in normal bovine chondrocytes and osteoarthritic human chondrocytes cultured in monolayer. This study also investigated the synergic or additive effects of these compounds. Enzymatically isolated primary bovine or human chondrocytes were cultured in monolayer until confluence and then incubated for 24 hours or 48 hours in the absence or in the presence of interleukin-1β and with or without curcuminoids extract, hydrolyzed collagen or green tea extract, added alone or in combination, at different concentrations. Cell viability was neither affected by these compounds, nor by interleukin 1β. In the absence of interleukin-1β, compounds did not significantly affect bovine chondrocytes metabolism. In human chondrocytes and in the absence of interleukin 1β, curcuminoids extract alone or in combination with hydrolyzed collagen and green tea extract significantly inhibited matrix metalloproteinase-3 production. In interleukin-1β-stimulated bovine chondrocytes, interleukin-6, inducible nitric oxide synthase, cyclooxygenase2, matrix metalloproteinase 3, a disintegrin and metalloproteinase with thrombospondin type I motifs 4 and a disintegrin and metalloproteinase with thrombospondin type I motifs 5 expressions were decreased by curcuminoids extract alone or in combination with hydrolyzed collagen and green tea extract. The combination of the three compounds was significantly more efficient to inhibit interleukin-1β stimulated matrix metalloproteinase-3 expression than curcuminoids extract alone. In interleukin-1β-stimulated human chondrocytes, nitric oxide, interleukin-6 and matrix metalloproteinase 3 productions were significantly reduced by curcuminoids extract alone or in combination with hydrolyzed collagen and green tea extract. These findings indicate that a mixture of curcuminoids extract, hydrolyzed collagen and green tea extract has beneficial effects on chondrocytes culture in inflammatory conditions and provide a preclinical basis for the in vivo testing of this mixture.

Anti-inflammatory effects of Vitis thunbergii var. taiwaniana on knee damage associated with arthritis

Vitis thunbergii Sieb. et Zucc. var. taiwaniana Lu (VT) is an indigenous plant in Taiwan that is traditionally used for promoting joint health. In this study, we used in vitro primary human chondrocytes (PHCs) and two in vivo animal models to evaluate the anti-inflammatory effects of VT on arthritis. Results showed that the water extract of the stems and roots from VT (VT-SR) was rich in flavones and phenols with 1.1 mg/g of resveratrol, 6.7 mg/g of hopeaphenol, and 5.1 mg/g of (+)-ɛ-viniferin. VT-SR significantly scavenged DPPH radicals and inhibited prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-induced PHCs without exhibiting significant cytotoxicity. In in vivo models, the VT-SR (500 mg/kg) significantly decreased serum PGE2 and knee 2-(18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) levels in LPS-induced acute inflammatory arthritis in rabbits. In addition, dietary supplementation with VT-SR for 28 days significantly alleviated type II collagenase-induced rat osteoarthritis with improvements in weight bearing and range of motion tests. In conclusion, our results suggest that the VT-SR is a good candidate for developing dietary supplements to prevent joint deterioration and inhibit inflammation.

Effect of epigallocatechin-3-gallate on proliferation and phenotype maintenance in rabbit articular chondrocytes in vitro

In autologous chondrocyte implantation (ACI) to restore defective cartilage, limited cell numbers and dedifferentiation of chondrocytes are the major difficulties. An alternative is the use of growth factors, but their high cost and potential for tumorigenesis are major obstacles. To ensure successful ACI therapy, it is important to find an effective substitute pro-chondrogenic agent. Epigallocatechin-3-gallate (EGCG), one of the green tea catechins, has been widely investigated in studies of interleukin-1β-induced chondrocytes. In the present study, the effects of EGCG on rabbit articular chondrocytes were investigated through the examination of cell proliferation, morphology, glycosaminoglycan synthesis and cartilage-specific gene expression. The results showed that EGCG could effectively promote chondrocyte growth and enhance the secretion and synthesis of the cartilage extracellular matrix by upregulating expression levels of aggrecan, collagen II and Sox9 genes. Expression of the collagen I gene was downregulated, which showed that EGCG effectively inhibited the dedifferentiation of chondrocytes. Hypertrophy, which may lead to chondrocyte ossification, was also undetectable in the EGCG groups. In conclusion, the recommended dose of EGCG was found to be in the range of 5 to 20 μM, with the most marked response observed with 10 μM. The present study may provide a basis for the development of a novel agent as a substitute for growth factors in the treatment of articular cartilage defects.