Ascorbic acid provides protection for human chondrocytes against oxidative stress

Development of Proniosome Gel Formulation for CHIKV Infection

Given the increasing aging population and the rising prevalence of musculoskeletal diseases due to obesity and injury, urgent research is needed to formulate new treatment alternatives, as current options remain inadequate. Viruses can exacerbate arthritis and worsen symptoms in patients with pre-existing osteoarthritis. Over the past decade, the chikungunya virus (CHIKV) has emerged as a significant public health concern, especially in Asia and South America. Exploring natural products, such as berberine, has shown promise due to its anticatabolic, antioxidative, and anti-inflammatory effects. However, berberine's low stability and bioavailability limit its efficacy. We hypothesized that encapsulating berberine into a proniosome gel, known for its ease of preparation and stability, could enhance its bioavailability and efficacy when applied topically, potentially treating CHIKV infection. Our investigation focused on how varying berberine loads and selected excipients in the proniosome gel influenced its physical properties, stability, and skin permeability. We also examined the biological half-life of berberine in plasma upon topical administration in mice to assess the potential for controlled and sustained drug release. Additionally, we analyzed the antioxidant stress activity and cell viability of HaCaT keratinocytes and developed a lipopolysaccharide-stimulated cell culture model to evaluate anti-inflammatory effects using pro-inflammatory cytokines. Overall, the research aims to transform the treatment landscape for arthritis by leveraging berberine's therapeutic potential.

Protective Effect of Ergothioneine against Oxidative Stress-Induced Chondrocyte Death

Reactive oxygen species (ROS) induce oxidative stress in cells and are associated with various diseases, including autoimmune diseases. Ergothioneine (EGT) is a natural amino acid derivative derived from the ergot fungus and has been reported to exhibit an effective antioxidant function in many models of oxidative stress-related diseases. Recently, mutations in OCTN1, a membrane transporter of EGT, have been reported to be associated with rheumatoid arthritis. Therefore, we investigated the chondrocyte-protective function of EGT using a model of oxidative stress-induced injury of chondrocytes by hydrogen peroxide (H2O2). Human chondrocytes were subjected to oxidative stress induced by H2O2 treatment, and cell viability, the activity of lactate dehydrogenase (LDH) released into the medium, dead cell ratio, intracellular ROS production, and mitochondrial morphology were assessed. EGT improved chondrocyte viability and LDH activity in the medium and strongly suppressed the dead cell ratio. EGT also exerted protective effects on intracellular ROS production and mitochondrial morphology. These results provide evidence to support the protective effects of EGT on chondrocytes induced by oxidative stress.

Exploring Ascorbic Acid's Role in Orthopedic Practices: Present Theories, Innovative Approaches, and Prospects

In the human body, ascorbic acid (AA) is known for its potent antioxidant and reducing properties and also plays a vital role in supporting the growth of bones and cartilage. It has been used extensively in orthopedic surgery. Ongoing studies under the umbrella of ascorbic acid research investigate its impact on bone and tendon physiology, as well as its influence on joint replacement and postoperative pain. The majority of both laboratory and human studies link the usage of ascorbic acid to enhanced bone health and improved tendon healing. Recent literature suggest that ascorbic acid administration may have a positive impact on the outcome of orthopedic procedures. On the other hand, controversy exists regarding the efficacy of ascorbic acid in reducing the incidence of complex regional pain syndrome. In brief, the effectiveness of ascorbic acid in enhancing orthopedic procedure outcomes remains a subject of ongoing investigation. Although certain studies have hinted at the potential positive influence of ascorbic acid on these outcomes, further research is required to validate its effectiveness and ascertain the ideal dosage and method of administration for maximizing its anticipated advantages. To establish the efficacy of ascorbic acid in improving orthopedic procedure outcomes, rigorous human trials of high quality are imperative. The aim of this review was to provide an overview of ascorbic acid's utilization in orthopedic practices and to pinpoint prospective areas for future research.

Intra-articular injection of ascorbic acid enhances microfracture-mediated cartilage repair

Previous studies have confirmed that ascorbic acid (AA) can promote cartilage repair and improve cartilage differentiation in bone marrow mesenchymal stem cells. However, the use of microfracture (MFX) combined with AA to repair cartilage damage has not been studied. This study established a rabbit animal model and treated cartilage injury with different concentrations of AA combined with MFX. Macroscopic observations, histological analysis, immunohistochemical analysis and reverse transcription quantitative polymerase chain reaction analysis of TGF-β, AKT/Nrf2, and VEGF mRNA expression were performed. The results showed that intra-articular injection of AA had a positive effect on cartilage repair mediated by microfractures. Moreover, 10 mg/ml AA was the most effective at promoting cartilage repair mediated by microfractures. Intra-articular injection of AA promoted the synthesis of type II collagen and the formation of glycosaminoglycans by downregulating the mRNA expression of TGF-β and VEGF. In summary, this study confirmed that AA could promote cartilage repair after MFX surgery.

Human Chondrocytes, Metabolism of Articular Cartilage, and Strategies for Application to Tissue Engineering

Hyaline cartilage, which is characterized by the absence of vascularization and innervation, has minimal self-repair potential in case of damage and defect formation in the chondral layer. Chondrocytes are specialized cells that ensure the synthesis of extracellular matrix components, namely type II collagen and aggregen. On their surface, they express integrins CD44, α1β1, α3β1, α5β1, α10β1, αVβ1, αVβ3, and αVβ5, which are also collagen-binding components of the extracellular matrix. This article aims to contribute to solving the problem of the possible repair of chondral defects through unique methods of tissue engineering, as well as the process of pathological events in articular cartilage. In vitro cell culture models used for hyaline cartilage repair could bring about advanced possibilities. Currently, there are several variants of the combination of natural and synthetic polymers and chondrocytes. In a three-dimensional environment, chondrocytes retain their production capacity. In the case of mesenchymal stromal cells, their favorable ability is to differentiate into a chondrogenic lineage in a three-dimensional culture.

A standardized nutraceutical supplement contributes to pain relief, improves quality of life and regulates inflammation in knee osteoarthritis patients; A randomized clinical trial

Osteoarthritis (OA) is a degenerative disease of the joints that affects greatly the elderly population and the health care systems and is on the increase due to aging and obesity. Interventions aim at palliative care and pharmaceutical therapies entail serious adverse events. Whereas polyphenols constitute a promising holistic approach in the arsenal of physicians, trials investigating biomarkers and questionnaires are scarce. As such, a randomized controlled trial (RCT) was conducted to evaluate the potency of a standardized polyphenolic supplement in the management of systemic inflammation, oxidative stress, pain and general quality of life (QoL) in patients with osteoarthritis. Sixty subjects were randomized to receive either a polyphenol supplement (curcuma phospholipid, rosemary extract, resveratrol, ascorbic acid), or an active comparator (ascorbic acid) twice, daily for 12 weeks. The group that received the polyphenols exhibited significantly lower symptoms of pain and improved physical function and QoL as it was depicted by validated questionnaires, compared to the control group. Furthermore, post intervention, inflammation was restrained in the polyphenol group. Since systemic inflammation promotes local inflammation, the decrease of pain herein might be attributed to the attenuation of systemic inflammation by the polyphenols.

Hyaluronic acid and multiwalled carbon nanotubes as bioink additives for cartilage tissue engineering

Articular cartilage and meniscus injuries are prevalent disorders with insufficient regeneration responses offered by available treatment methods. In this regard, 3D bioprinting has emerged as one of the most promising new technologies, offering novel treatment options. Additionally, the latest achievements from the fields of biomaterials and tissue engineering research identified constituents facilitating the creation of biocompatible scaffolds. In this study, we looked closer at hyaluronic acid and multi-walled carbon nanotubes as bioink additives. Firstly, we assessed the minimal concentrations that stimulate cell viability, and decrease reactive oxygen species and apoptosis levels in 2D cell cultures of normal human knee articular chondrocytes (NHAC) and human adipose-derived mesenchymal stem cells (hMSC-AT). In this regard, 0.25 mg/ml of hyaluronic acid and 0.0625 mg/ml of carbon nanotubes were selected as the most optimal concentrations. In addition, we investigated the protective influence of 2-phospho-L-ascorbic acid in samples with carbon nanotubes. Tests conducted on 3D bioprinted constructs revealed that only a combination of components positively impacted cell viability throughout the whole experiment. Gene expression analysis of COL1A1, COL6A1, HIF1A, COMP, RUNX2, and POU5F1 showed significant changes in the expression of all analyzed genes with a progressive overall loss of transcriptional activity in most of them.

Ageing and Osteoarthritis Synergically Affect Human Synoviocyte Cells: An In Vitro Study on Sex Differences

Osteoarthritis is a chronic inflammatory disease that affects all of the joints, especially those of the elderly. Aging is a natural and irreversible biological process implicated in the pathophysiology of many chronic diseases, such as osteoarthritis. Inflammation and oxidative stress are the main factors involved in osteoarthritis and aging, respectively, with the production of several pro-inflammatory cytokines such as Interleukin 1β (IL1β) and reactive oxygen species. The aim of the study was to set-up an in vitro model of osteoarthritis and aging, focusing on the sex differences by culturing male and female fibroblast-like synoviocytes (FLSs) with IL1β, hydrogen peroxide (H₂O₂), IL1β+H₂O₂ or a growth medium (control). IL1β+H₂O₂ reduced the cell viability and microwound healing potential, increased Caspase-3 expression and reactive oxygen species and IL6 production; IL1β increased IL6 production more than the other conditions did; H₂O₂ increased Caspase-3 expression and reactive oxygen species production; Klotho expression showed no differences among the treatments. The FLSs from female donors demonstrated a better response capacity in unfavorable conditions of inflammation and oxidative stress than those from the male donors did. This study developed culture conditions to mimic the aging and osteoarthritis microenvironment to evaluate the behavior of the FLSs which play a fundamental role in joint homeostasis, focusing on the sex-related aspects that are relevant in the osteoarthritis pathophysiology.

Primary growth plate chondrocyte isolation, culture, and characterization from the modern broiler

Lameness is a leading cause of animal welfare and production concerns for the poultry industry as fast-growing, high-yielding broilers seem more susceptible to bone disease and infections. A major limitation to the study of these disorders is the lack of a chicken immortalized chondrocyte cell. Primary cell isolation is a valid and complex method for establishing a relevant in vitro model for diseases. In this study, isolation and high-density culturing of primary chondrocytes form 1-d old chicks was followed by confirmation of cell type, identification of optimal phenotypic expression, and evaluation of cells functionality. mRNA expression, as well as protein production and secretion, of COLI, COLII, Sox9, ACAN, and COLXA1 on day 3 (d3), d7, d11, d14, d18, and d21 in culture showed that avian growth plate chondrocytes under these conditions exhibit optimal phenotypes from d3 to d7. This is evident by a shift from COLII dominant expression in early-culture to COLI dominant expression by late-culture in conjunction with a loss of other chondrocyte markers Sox9, ACAN, and COLXA1. Additionally, morphological changes seen through live cell imaging coincide with the shift of phenotype in mid- to late-culture periods indicating a dedifferentiated phenotype. The functionality of the cultured cells was confirmed using Brefeldin-A treatment which significantly reduced secretion of COLII by d7 chondrocytes. These results provide a foundation for future research utilizing avian primary chondrocytes with optimal phenotypes for disease modeling or passaging.

Interleukin 1β and lipopolysaccharides induction dictate chondrocyte morphological properties and reduce cellular roughness and adhesion energy comparatively

Osteoarthritis (OA) is a whole joint disease marked by the degradation of the articular cartilage (AC) tissue, chronic inflammation, and bone remodeling. Upon AC's injury, proinflammatory mediators including interleukin 1β (IL1β) and lipopolysaccharides (LPS) play major roles in the onset and progression of OA. The objective of this study was to mechanistically detect and compare the effects of IL1β and LPS, separately, on the morphological and nanomechanical properties of bovine chondrocytes. Cells were seeded overnight in a full serum medium and the next day divided into three main groups: A negative control (NC) of a reduced serum medium and 10 ng/ml IL1ß or 10 ng/ml LPS-modified media. Cells were induced for 24 h. Nanomechanical properties (elastic modulus and adhesion energy) and roughness were quantified using atomic force microscopy. Nitric oxide, prostaglandin 2 (PGE2), and matrix metalloproteinases 3 (MMP3) contents; viability of cells; and extracellular matrix components were quantified. Our data revealed that viability of the cells was not affected by inflammatory induction and IL1ß induction increased PGE2. Elastic moduli of cells were similar among IL1β and NC while LPS significantly decreased the elasticity compared to NC. IL1ß induction resulted in least cellular roughness while LPS induction resulted in least adhesion energy compared to NC. Our images suggest that IL1ß and LPS inflammation affect cellular morphology with cytoskeleton rearrangements and the presence of stress fibers. Finally, our results suggest that the two investigated inflammatory mediators modulated chondrocytes' immediate responses to inflammation in variable ways.

Effectiveness of Clinical-Grade Chondroitin Sulfate and Ascorbic Acid in Mitigating Cryoprotectant Toxicity in Porcine Articular Cartilage

High concentrations of cryoprotective agents (CPAs) are required to achieve successful vitrification of articular cartilage; however, CPA cytotoxicity causes chondrocyte death. To reduce CPA toxicity, supplementation with research-grade additives, in particular chondroitin sulfate (CS) and ascorbic acid (AA), have previously been shown to improve chondrocyte recovery and metabolic function after exposure to CPAs at hypothermic conditions. However, it is necessary to evaluate the pharmaceutical equivalent clinical grade of these additives to facilitate the supplementation of additives into future vitrification protocols, which will be designed for vitrifying human articular cartilage in tissue banks. We sought to investigate the effectiveness of clinical-grade CS, AA, and N-acetylcysteine (NAC) in mitigating toxicity to chondrocytes during CPA exposure and removal, and determine whether a combination of two additives would further improve chondrocyte viability. We hypothesized that clinical-grade additives would exert chondroprotective effects comparable to those of research-grade additives, and that this protective effect would be enhanced if two additives were combined when compared with a single additive. The results indicated that both clinical-grade and research-grade additives significantly improved cell viability (p < 0.10) compared with the negative control (CPA with no additives). CS, AA, and NAC+AA increased cell viability significantly (p < 0.10) compared with the negative control. However, NAC, NAC+CS, and CS+AA did not improve cell viability when compared with the negative control (p > 0.10). We demonstrated that supplementation with clinical-grade CS or AA significantly improved chondrocyte viability in porcine cartilage subjected to high CPA concentrations, whereas supplementation with clinical-grade NAC did not benefit chondrocyte viability. Supplementation with clinical-grade additives in CPA solutions can mitigate CPA toxicity, which will be important in translating previously developed effective protocols for the vitrification of articular cartilage to human tissue banks.

The Role of Antioxidants in the Interplay between Oxidative Stress and Senescence

Cellular senescence is an irreversible state of cell cycle arrest occurring in response to stressful stimuli, such as telomere attrition, DNA damage, reactive oxygen species, and oncogenic proteins. Although beneficial and protective in several physiological processes, an excessive senescent cell burden has been involved in various pathological conditions including aging, tissue dysfunction and chronic diseases. Oxidative stress (OS) can drive senescence due to a loss of balance between pro-oxidant stimuli and antioxidant defences. Therefore, the identification and characterization of antioxidant compounds capable of preventing or counteracting the senescent phenotype is of major interest. However, despite the considerable number of studies, a comprehensive overview of the main antioxidant molecules capable of counteracting OS-induced senescence is still lacking. Here, besides a brief description of the molecular mechanisms implicated in OS-mediated aging, we review and discuss the role of enzymes, mitochondria-targeting compounds, vitamins, carotenoids, organosulfur compounds, nitrogen non-protein molecules, minerals, flavonoids, and non-flavonoids as antioxidant compounds with an anti-aging potential, therefore offering insights into innovative lifespan-extending approaches.

Monocyte Chemotactic Proteins Mediate the Effects of Hyperglycemia in Chondrocytes: In Vitro Studies

Chemokines are secreted by a large variety of cells. They are involved in controlling cell trafficking, maturation, and differentiation. However, the specific responses and effects of chemokines on specific skeletal cell types under high glucose conditions have not been investigated. Chondrocytes play an important role in osteoarthritis and fracture healing. Delayed fracture healing is one of the major health complications caused by diabetes, so the goal of this study was to evaluate the response of several chemokines to high glucose conditions in chondrocyte cells and analyze their role in the catabolic effect of hyperglycemia. ATDC5 chondrocytes were cultured in normal and high glucose media, and mRNA expression levels of several chemokines and chondrocyte differentiation markers were quantified. Bindarit, a specific inhibitor of monocyte chemotactic proteins (MCPs), was used to determine the role of MCPs in mediating the effects of high glucose conditions in chondrocyte cells. High glucose treatment upregulated the expression of three Mcps, as well as the expression of matrix metalloproteinase 13 (Mmp13) and Osteocalcin (Oc). Furthermore, bindarit treatment downregulated Mmp13 and Oc but upregulated Collagen 2 (Col2) mRNA levels in chondrocytes treated with high glucose. Moreover, treatment of chondrocytes with ascorbic acid reduced the effect of high glucose conditions on the expression of chemokines and Mmps. These data together suggest that MCPs mediate the catabolic effect of high glucose in chondrocytes.

Nutraceutical Approach to Chronic Osteoarthritis: From Molecular Research to Clinical Evidence

Osteoarthritis (OA) is a degenerative inflammatory condition of the joint cartilage that currently affects approximately 58 million adults in the world. It is characterized by pain, stiffness, and a reduced range of motion with regard to the arthritic joints. These symptoms can cause in the long term a greater risk of overweight/obesity, diabetes mellitus, and falls and fractures. Although the current guidelines for the treatment of OA suggest, as the gold standard for this condition, pharmacological treatment characterized by non-steroidal anti-inflammatory drugs (NSAID), opioids, and cyclooxygenase (COX)-2-specific drugs, a great interest has been applied to nutraceutical supplements, which include a heterogeneous class of molecules with great potential to reduce inflammation, oxidative stress, pain, and joint stiffness and improve cartilage formation. The purpose of this review is to describe the potential application of nutraceuticals in OA, highlighting its molecular mechanisms of actions and data of efficacy and safety (when available).

Sex-Specific Reduction in Inflammation of Osteoarthritic Human Chondrocytes and Nutraceutical-Dependent Extracellular Matrix Formation

Introduction

The aim of this study was to investigate the ability of osteoarthritic human chondrocytes to produce articular cartilage (AC) tissues with a reduced inflammatory environment in response to 4 anti-inflammatory nutraceuticals: alpha-tocopherol (Alpha), gallic acid (G), ascorbic acid (AA), and catechin hydrate (C).

Methods

Chondrocytes isolated from patients who underwent total knee arthroplasty surgeries were divided into groups (9 male; mean age, 66.2 ± 3.5 years and 11 female; mean age, 64.2 ± 3.1 years). Cells were cultured based on sex and supplemented with either a negative control (NC) medium or NC plus one of the nutraceuticals at a concentration of 50 μM. At day 21, cultures were characterized histologically, biochemically, and for gene expression of vital markers.

Results

At day 21, 62.3% and 66.2% reduction in nitric oxide (NO) content was evident for female and male cells, respectively. G-treatment of female cells resulted in the lowest expression of nitric oxide synthase-2 (NOS2), matrix metalloproteinase-13 (MMP13), and collagen type-10 (COL10). Alpha-treatment of male cells resulted in the lowest expression of NOS2, bone morphogenic protein-2, MMP13, COL10 and tumor necrosis factor alpha induced protein-6 (TNFAIP6) relative to NC. AA and Alpha treatment resulted in the highest glycosaminoglycan (GAG) content for female and male cultures, respectively.

Conclusion

A sex-dependent response of osteoarthritic chondrocytes to nutraceutical treatment was evident. Our results suggest the use of G for female cells and Alpha for male cells in OA applications seems to be favorable in reducing inflammation and enhancing chondrocytes' ability to form AC tissues.

Vitamin C supplementation for the treatment of osteoarthritis: perspectives on the past, present, and future

According to the US Centers for Disease Control and Prevention (CDC), an estimated 14% of adults in the United States have either been diagnosed with osteoarthritis (OA) or have symptoms suggestive of the disease. The CDC also points out that the incidence of OA has been gradually increasing over the past 30 years. What is more worrisome is that this trend is going to accelerate due to the aging demographics of the United States and the increasing prevalence of obesity seen in the country. The need for better preventive treatments and efficacious therapeutics are direly needed to combat this public health crisis. Among the possible treatments being hypothesized, antioxidant supplementation has become one of the most widely studied over the past decade due to its ability to attenuate reactive oxygen species (ROS) formation within chondrocytes, a critical step in the pathogenesis of this disease. Vitamin C has emerged as among the most promising of the antioxidant group, with many animal and human studies having been conducted in recent years. Although many of the studies have shown encouraging results in terms of preventing OA, others have reached opposite conclusions, thus making the data controversial. However, after reviewing several of these studies, we hypothesize that certain parameters may not have been properly considered during data collection. In the end, more randomized placebo-controlled trials in humans are desperately needed in order to fully understand whether vitamin C therapy is efficacious in treating and/or preventing OA.

Chondrocyte Aging: The Molecular Determinants and Therapeutic Opportunities

Osteoarthritis (OA) is a joint degenerative disease that is an exceedingly common problem associated with aging. Aging is the principal risk factor for OA, but damage-related physiopathology of articular chondrocytes probably drives the mechanisms of joint degeneration by a progressive decline in the homeostatic and regenerative capacity of cells. Cellular aging is the manifestation of a complex interplay of cellular and molecular pathways underpinned by transcriptional, translational, and epigenetic mechanisms and niche factors, and unraveling this complexity will improve our understanding of underlying molecular changes that affect the ability of the articular cartilage to maintain or regenerate itself. This insight is imperative for developing new cell and drug therapies for OA disease that will target the specific causes of age-related functional decline. This review explores the key age-related changes within articular chondrocytes and discusses the molecular mechanisms that are commonly perturbed as cartilage ages and degenerates. Current efforts and emerging potential therapies in treating OA that are being employed to halt or decelerate the aging processes are also discussed.

Doxycycline preserves chondrocyte viability and function in human and calf articular cartilage ex vivo

Prolonging chondrocyte survival is essential to ensure fresh osteochondral (OC) grafts for treatment of articular cartilage lesions. Doxycycline has been shown to enhance cartilage growth, disrupt terminal differentiation of chondrocytes, and inhibit cartilage matrix degradation. It is unknown whether doxycycline prolongs chondrocyte survival in OC grafts. We hypothesized that doxycycline protects against chondrocyte death and maintains function of articular cartilage. To test this hypothesis, we employed human and calf articular cartilages, and incubated chondrocytes isolated from cartilage or cartilage plugs with doxycycline (0, 1 or 10 μg/ml) at either 37°C or 4°C. Chondrocyte viability, apoptosis, glycosaminoglycan (GAG), collagen, and mechanical test in cartilage plugs were measured. We found that reduced chondrocyte viability, increased chondrocyte apoptosis, reduced GAG contents, and impaired equilibrium modulus in cartilage plugs were observed in a time-dependent manner at both 37°C and 4°C. Chondrocyte viability was further reduced when the plugs were cultured at 4°C as compared to 37°C. Doxycycline prolonged viability and reduced apoptosis of chondrocytes during culture of cartilage plugs. Functionally, doxycycline protected against reduced production of GAG and collagen II as well as impaired mechanical properties in cartilage plugs during culture. Mechanistically, doxycycline increased mitochondrial respiration in cultured chondrocytes. In conclusion, preservation at 37°C is beneficial for maintaining chondrocyte viability in cartilage plugs compared to 4°C. Incubation of doxycycline protects against chondrocyte apoptosis, reduced extracellular matrix, and impaired mechanical properties in cartilage plugs. The findings provide a potential approach using doxycycline at 37°C to preserve chondrocyte viability in fresh OC grafts for treatment of articular cartilage lesions.

Vitamin C in orthopedic practices: Current concepts, novel ideas, and future perspectives

Vitamin C (ascorbic acid), is an important antioxidant that has been applied broadly in the field of orthopaedics. Current research on vitamin C examines the molecule's role in bone and tendon physiology, as well as joint replacement and Postoperative pain. Most laboratory and human studies associate the use of vitamin C with improved bone health and tendon healing. Recent literature moderately supports the use of vitamin C to improve functional outcomes, decreased postoperative pain, and prevent complex regional pain syndrome following orthopaedic procedures. The perioperative use of vitamin C in patients undergoing joint replacement surgery and anterior cruciate ligament reconstruction is still under investigation. Overall, there is need for high-quality human trials to confirm whether vitamin C can potentiate the outcomes of orthopaedic procedures and to determine optimal dosage and means of administration to maximize its proposed benefits. The purpose of this review was to summarize the application of vitamin C in orthopaedic practices and to identify potential areas for future study.

Establishing SW1353 Chondrocytes as a Cellular Model of Chondrolysis

Osteoarthritis (OA) is the most common degenerative joint disease characterised by chondrocyte cell death. An in vitro model of chondrocyte cell death may facilitate drug discovery in OA management. In this study, the cytotoxicity and mode of cell death of SW1353 chondrocytes treated with 24 h of OA inducers, including interleukin-1β (IL-1β), hydrogen peroxide (H2O2) and monosodium iodoacetate (MIA), were investigated. The microscopic features, oxidative (isoprostane) and inflammatory markers (tumour necrosis factor-alpha; TNF-α) for control and treated cells were compared. Our results showed that 24 h of H2O2 and MIA caused oxidative stress and a concentration-dependent reduction of SW1353 cell viability without TNF-α level upregulation. H2O2 primarily induced chondrocyte apoptosis with the detection of blebbing formation, cell shrinkage and cellular debris. MIA induced S-phase arrest on chondrocytes with a reduced number of attached cells but without significant cell death. On the other hand, 24 h of IL-1β did not affect the cell morphology and viability of SW1353 cells, with a significant increase in intracellular TNF-α levels without inducing oxidative stress. In conclusion, each OA inducer exerts differential effects on SW1353 chondrocyte cell fate. IL-1β is suitable in the inflammatory study but not for chondrocyte cell death. H2O2 and MIA are suitable for inducing chondrocyte cell death and growth arrest, respectively.

In Vitro Effects of Low Doses of β-Caryophyllene, Ascorbic Acid and d-Glucosamine on Human Chondrocyte Viability and Inflammation

β-caryophyllene (BCP), a plant-derived sesquiterpene, has been reported to have anti-inflammatory and antioxidant effects. The purpose of this study is to evaluate the effects of BCP in combination with ascorbic acid (AA) and d-glucosamine (GlcN) against macrophage-mediated inflammation on in vitro primary human chondrocytes. Changes in cell viability, intracellular ROS generation, gene expression of pro-inflammatory mediators, metalloproteinases (MMPs), collagen type II and aggrecan were analyzed in primary human chondrocytes exposed to the conditioned medium (CM) of activated U937 monocytes and subsequently treated with BCP alone or in combination with AA and GlcN. The CM-induced chondrocyte cytotoxicity was reduced by the presence of low doses of BCP alone or in combination with AA and GlcN. The exposure of cells to CM significantly increased IL-1β, NF-κB1 and MMP-13 expression, but when BCP was added to the inflamed cells, alone or in combination with AA and GlcN, gene transcription for all these molecules was restored to near baseline values. Moreover, chondrocytes increased the expression of collagen type II and aggrecan when stimulated with AA and GlcN alone or in combination with BCP. This study showed the synergistic anti-inflammatory and antioxidative effects of BCP, AA and GlcN at low doses on human chondrocyte cultures treated with the CM of activated U937 cells. Moreover, the combination of the three molecules was able to promote the expression of collagen type II and aggrecan. All together, these data could suggest that BCP, AA and GlcN exert a chondro-protective action.

The role of SIRT3-mediated mitochondrial homeostasis in osteoarthritis

Osteoarthritis is the most common degenerative joint disease and causes major pain and disability in adults. It has been reported that mitochondrial dysfunction in chondrocytes is associated with osteoarthritis. Sirtuins are a family of nicotinamide adenine dinucleotide-dependent histone deacetylases that have the ability to deacetylate protein targets and play an important role in the regulation of cell physiological and pathological processes. Among sirtuin family members, sirtuin 3, which is mainly located in mitochondria, can exert its deacetylation activity to regulate mitochondrial function, regeneration, and dynamics; these processes are presently recognized to maintain redox homeostasis to prevent oxidative stress in cell metabolism. In this review, we provide present opinions on the effect of mitochondrial dysfunction in osteoarthritis. Furthermore, the potential protective mechanism of SIRT3-mediated mitochondrial homeostasis in the progression of osteoarthritis is discussed.

Antioxidant additives reduce reactive oxygen species production in articular cartilage during exposure to cryoprotective agents

High concentrations of cryoprotective agents (CPA) are required during articular cartilage cryopreservation but these CPAs can be toxic to chondrocytes. Reactive oxygen species have been linked to cell death due to oxidative stress. Addition of antioxidants has shown beneficial effects on chondrocyte survival and functions after cryopreservation. The objectives of this study were to investigate (1) oxidative stress experienced by chondrocytes and (2) the effect of antioxidants on cellular reactive oxygen species production during articular cartilage exposure to high concentrations of CPAs. Porcine cartilage dowels were exposed to a multi-CPA solution supplemented with either 0.1 mg/mL chondroitin sulfate or 2000 μM ascorbic acid, at 4 °C for 180 min (N = 7). Reactive oxygen species production was measured with 5 μM dihydroethidium, a fluorescent probe that targets reactive oxygen species. The cell viability was quantified with a dual cell membrane integrity stain containing 6.25 μM Syto 13 + 9 μM propidium iodide using confocal microscopy. Supplementation of CPA solutions with chondroitin sulfate or ascorbic acid resulted in significantly lower dihydroethidium counts (p < 0.01), and a lower decrease in the percentage of viable cells (p < 0.01) compared to the CPA-treated group without additives. These results indicated that reactive oxygen species production is induced when articular cartilage is exposed to high CPA concentrations, and correlated with the amount of dead cells. Both chondroitin sulfate and ascorbic acid treatments significantly reduced reactive oxygen species production and improved chondrocyte viability when articular cartilage was exposed to high concentrations of CPAs.

Role of Vitamin C in Osteoporosis Development and Treatment-A Literature Review

Osteoporosis and associated low energy fractures are a significant clinical problem, especially in the elderly population. The occurrence of a hip fracture is associated with significant mortality and a high risk of disability. For this, apart from the treatment of osteoporosis, effective prevention of both the development of the disease and related fractures is extremely important. One aspect of osteoporosis prevention is proper dietary calcium intake and normal vitamin D3 levels. However, there is some evidence for a potential role of vitamin C in osteoporosis and fracture prevention, too. This review aims to summarize the current knowledge about the role of vitamin C in osteoporosis development, prevention and treatment. The PubMed/Medline search on the role of vitamin C in bone metabolism database was performed for articles between 2000 and May 2020. Reports from in vitro and animal studies seem promising. Epidemiological studies also indicate the positive effect of high vitamin C content in the daily diet on bone mineral density. Despite promising observations, there are still few observational and intervention studies and their results do not allow for unequivocal determination of the benefits of high daily intake of vitamin C or its long-term supplementation.

Roles of vitamins in stem cells

Stem cells can differentiate to diverse cell types in our body, and they hold great promises in both basic research and clinical therapies. For specific stem cell types, distinctive nutritional and signaling components are required to maintain the proliferation capacity and differentiation potential in cell culture. Various vitamins play essential roles in stem cell culture to modulate cell survival, proliferation and differentiation. Besides their common nutritional functions, specific vitamins are recently shown to modulate signal transduction and epigenetics. In this article, we will first review classical vitamin functions in both somatic and stem cell cultures. We will then focus on how stem cells could be modulated by vitamins beyond their nutritional roles. We believe that a better understanding of vitamin functions will significantly benefit stem cell research, and help realize their potentials in regenerative medicine.

Taurine alleviates endoplasmic reticulum stress in the chondrocytes from patients with osteoarthritis

Osteoarthritis (OA), characterized by pain and stiffness, swelling, deformity and dysfunction of joints, affects large numbers of population. The purpose of this study was to discover the effects of taurine in human OA chondrocytes and explore the underlying mechanisms. 46 patients with different grades of OA were recruited. Of these patients, 24 underwent total knee replacement and cartilages were harvested. The mRNA expressions of type II collagen (Collagen II) and endoplasmic reticulum (ER) stress markers (GRP78, GADD153 and Caspase-12) in cartilages were quantified by qRT-PCR. Cell viability and apoptosis of patient-derived chondrocytes were assessed by the CCK-8 assay and flow cytometry assay, respectively. Meanwhile, protein levels of Collagen II and ER stress markers both in cartilages and chondrocytes were evaluated by Western blot. The mRNA and protein levels of Collagen II decreased as OA progressed, while the expressions of ER stress markers increased dramatically. H₂O₂ induced ER stress in chondrocytes, as shown by the significant increase in the expression of ER stress markers, inhibited chondrocyte viability and Collagen II synthesis, promoted apoptosis. However, taurine treatment inhibited these above phenomena. These results indicated that taurine exhibited anti-OA effect by alleviating H₂O₂ induced ER stress and subsequently inhibiting chondrocyte apoptosis.

Ascorbic acid inhibits senescence in mesenchymal stem cells through ROS and AKT/mTOR signaling

Mesenchymal stem cell (MSC) aging seriously affects its function in stem cell transplantation for treatment. Extensive studies have focused on how to inhibit senescence in MSCs. However, the mechanism of senescence in MSC was not clear. In this study, we used D-galactose to induce MSC aging. Then we found that the number of aging cells was increased compared with untreated MSCs. We discovered that ascorbic acid could inhibit the production of reactive oxygen species (ROS) and activation of AKT/mTOR signaling in MSCs caused by D-galactose. Especially, when treated together with a ROS scavenger or AKT inhibitor, the senescent cells were obviously decreased in D-galactose-induced MSCs. Taken together, we identify that ascorbic acid owns the potential to inhibit the senescence of MSCs through ROS and Akt/mTOR signaling. Together, our data supports that ascorbic acid can be used to prevent MSCs from senescence, which can enhance the efficiency of stem cell transplantation in the clinic.

[Intra-articular injection of ascorbic acid/ferric chloride relieves cartilage degradation in rats with osteoarthritis]

OBJECTIVE

To assess the effect of ascorbic acid/ferric chloride (AA/FeCl₃) in attenuating cartilage damage in rats with osteoarthritis.

METHODS

Thirty adult male Wistar rats with surgically induced osteoarthritis were randomized into 2 groups for treatment with intra-articular injection of saline (control group) or AA/FeCl3 mixture (AA group) once a week starting from the third week after the operation. At 6, 9, and 12 weeks after the operation, 5 rats from each group were sacrificed for observing subchondral bone changes on X-ray films and evaluation of cartilage degeneration in the right knee joints using safranin-O/Fast green staining and a modified OARSI scoring system. The degradation of the cartilage matrix was observed by immunohistochemical staining for type Ⅱ collagen.

RESULTS

X-ray examination in saline control group revealed the presence of osteophytes and narrowing of the joint space at 9 weeks, and the joint line disappeared at 12 weeks after the surgery; only slight irregularity of the articular surface was observed in the AA group at 9 and 12 weeks. OARSI scores were significantly lower in AA group than in the control group at 9 weeks (18.67±0.67 vs 12.17±2.75; P < 0.05) and 12 weeks (20.11±1.84 vs 13.77± 0.40; P < 0.05) but not at 6 weeks after the surgery. The content of type 2 collagen in AA group was significantly higher than that in the control group at 6 weeks (0.36±0.039 vs 0.49±0.029; P < 0.05) and 9 weeks after the surgery (0.25±0.041 vs 0.38±0.040; P < 0.05).

CONCLUSIONS

Early intra-articular injection of AA/FeCl₃ can effectively delay the progression of post-traumatic osteoarthritis in rats.

Could Oxidative Stress Regulate the Expression of MicroRNA-146a and MicroRNA-34a in Human Osteoarthritic Chondrocyte Cultures?

Oxidative stress and the overproduction of reactive oxygen species (ROS) play an important role in the pathogenesis of osteoarthritis (OA). Accumulating evidence has demonstrated the involvement of microRNAs (miRNAs) dysregulation in disease development and progression. In this study, we evaluated the effect of oxidative stress on miR-146a and miR-34a expression levels in human OA chondrocytes cultures stimulated by H₂O₂. Mitochondrial ROS production and cell apoptosis were detected by flow cytometry. The antioxidant enzymes SOD-2, CAT, GPx, the transcriptional factor NRF2 and the selected miRNAs were analyzed by qRT-PCR. The H₂O₂-induced oxidative stress was confirmed by a significant increase in superoxide anion production and of the apoptotic ratio. Furthermore, H₂O₂ significantly up-regulated the expression levels of SOD-2, CAT, GPx and NRF2, and modulated miR-146a and miR-34a gene expression. The same analyses were carried out after pre-treatment with taurine, a known antioxidant substance, which, in our experience, counteracted the H₂O₂-induced effect. In conclusion, the induction of oxidative stress affected cell apoptosis and the expression of the enzymes involved in the oxidant/antioxidant balance. Moreover, we demonstrated for the first time the modification of miR-146a and miR-34a in OA chondrocytes subjected to H₂O₂ stimulus and we confirmed the antioxidant effect of taurine.

Oxidative stress and chronic inflammation in osteoarthritis: can NRF2 counteract these partners in crime?

Osteoarthritis (OA) is an age-related joint degenerative disease associated with pain, joint deformity, and disability. The disease starts with cartilage damage but then progressively involves subchondral bone, causing an imbalance between osteoclast-driven bone resorption and osteoblast-driven remodeling. Here, we summarize the data for the role of oxidative stress and inflammation in OA pathology and discuss how these two processes are integrated during OA progression, as well as their contribution to abnormalities in cartilage/bone metabolism and integrity. At the cellular level, oxidative stress and inflammation are counteracted by transcription factor nuclear factor erythroid p45-related factor 2 (NRF2), and we describe the regulation of NRF2, highlighting its role in OA pathology. We also discuss the beneficial effect of some phytonutrients, including the therapeutic potential of NRF2 activation, in OA.

Cellular aging towards osteoarthritis

Osteoarthritis (OA) is a common form of degenerative joint disease. Aging process is supposed to be a leading predictor for developing OA. In this review, we have discussed the potential roles of aging in OA, a better understanding of which might delay or stop the development and progression of OA. Different cellular signaling mechanisms are involved process of aging that induces age-related changes in chondrocytes. These changes influence the expression of catabolic factors resulting in increased production of matrix metalloproteinases and cytokines, reduced levels of collagen type II and aggrecan synthesis, and increased production of reactive oxygen species (ROS). ROS leads to mitochondrial dysfunction and chondrocyte death, which contributes to the development of OA. Antioxidant supplementation is probably the best way to prevent or delay the age-related OA. Some therapeutic agents like histone deacetylase inhibitors and anti-miR34a agents have been reported to be effective against age-related OA. However, further research is needed to demonstrate the efficacy of these alternative treatment strategies in clinical trials using controlled and prospective studies.

Vitamin C Protects Chondrocytes against Monosodium Iodoacetate-Induced Osteoarthritis by Multiple Pathways

Osteoarthritis (OA) is the most prevalent joint disease. Dietary intake of vitamin C relates to a reduction in cartilage loss and OA. This study examined the efficacy of vitamin C to prevent OA with the in vitro chondrosarcoma cell line (SW1353) and the in vivo monosodium iodoacetate (MIA)-induced OA rat. Results demonstrated that, in SW1353 cells, treatment with 5 μM MIA inhibited cell growth and increased oxidative stress, apoptosis, and proteoglycan loss. In addition, the expression levels of the pro-inflammatory cytokines IL-6, IL-17A, and TNF-α and matrix metalloproteinases (MMPs) MMP-1, MMP-3, and MMP-13 were increased. All of these MIA-induced changes could be prevented with treatment of 100 μM vitamin C. In an animal model, intra-articular injection of MIA-induced cartilage degradation resembled the pathological changes of OA, and treatment of vitamin C could lessen these changes. Unexpectedly, vitamin C’s effects did not strengthen with the increasing dosage, while the 100 mg/kg dosage was more efficient than the 200 or 300 mg/kg dosages. Vitamin C possessed multiple capacities for prevention of OA progress, including a decrease in apoptosis and in the expression of pro-inflammatory cytokines and MMPs in addition to the well-known antioxidation.

Chondroprotective effects of alpha-lipoic acid in a rat model of osteoarthritis

OBJECTIVE

The purpose of this study was to investigate whether alpha-lipoic acid (ALA) confers a chondroprotective effect on articular cartilage in rats with monosodium iodoacetate (MIA)-induced osteoarthritis (OA).

METHODS

Fifty male SD rats were divided into five groups, including SHAM-operated, MIA-induced OA, and three experimental groups treated with 50-, 100-, or 200-mg/kg ALA. After 14 d of ALA treatment, rats were sacrificed for joint macroscopic and histology assessments. The gene and protein expressions of markers related to chondrocyte phenotype, caspase proteins, NADPH oxidase 4 (Nox4), p22(phox), activation of nuclear factor-κB (NF-κB), and endoplasmic reticulum (ER) stress were measured by Western blot analyses or qRT-PCR.

RESULTS

The results showed that MIA injection successfully induced OA by causing cartilage degeneration. Morphological and histological examinations demonstrated that ALA treatment, especially 200 mg/kg of ALA, significantly ameliorated cartilage degeneration in rats with MIA-induced OA. ALA could effectively increase the levels of the collagen type II and aggrecan genes and inhibit apoptosis-related proteins expression. ALA reduced biomakers of oxidative damage and over-expression levels of Nox4 and p22(phox). ALA also suppressed ER stress and inhibited the activation of NF-κB pathway. Moreover, ALA obviously inhibited TNF-α secretion and Wnt/β-catenin signaling way.

CONCLUSION

These findings indicated that ALA might be a potential therapeutic agent for the protection of articular cartilage against progression of OA through inhibition of oxidative stress, ER stress, inflammatory cytokine secretion, and Wnt/β-catenin activation.

ROS/oxidative stress signaling in osteoarthritis

Osteoarthritis is the most common joint disorder with increasing prevalence due to aging of the population. Its multi-factorial etiology includes oxidative stress and the overproduction of reactive oxygen species, which regulate intracellular signaling processes, chondrocyte senescence and apoptosis, extracellular matrix synthesis and degradation along with synovial inflammation and dysfunction of the subchondral bone. As disease-modifying drugs for osteoarthritis are rare, targeting the complex oxidative stress signaling pathways would offer a valuable perspective for exploration of potential therapeutic strategies in the treatment of this devastating disease.