Intra-Articular Injection of Cross-Linked Hyaluronic Acid-Dexamethasone Hydrogel Attenuates Osteoarthritis: An Experimental Study in a Rat Model of Osteoarthritis

Application of Injectable Hydrogels as Delivery Systems in Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis and rheumatoid arthritis, though etiologically distinct, are both inflammatory joint diseases that cause progressive joint injury, chronic pain, and loss of function. Therefore, long-term treatment with a focus on relieving symptoms is needed. At present, the primary treatment for arthritis is drug therapy, both oral and intravenous. Although significant progress has been achieved for these treatment methods in alleviating symptoms, certain prominent drawbacks such as the substantial side effects and limited absorption of medications call for an urgent need for improved drug delivery methods. Injected hydrogels can be used as a delivery system to deliver drugs to the joint cavity in a controlled manner and continuously release them, thereby enhancing drug retention in the joint cavity to improve therapeutic effectiveness, which is attributed to the desirable attributes of the delivery system such as low immunogenicity, good biodegradability and biocompatibility. This review summarizes the types of injectable hydrogels and analyzes their applications as delivery systems in arthritis treatment. We also explored how hydrogels counteract inflammation, bone and cartilage degradation, and oxidative stress, while promoting joint cartilage regeneration in the treatment of osteoarthritis (OA) and rheumatoid arthritis (RA). This review also highlights new approaches to developing injectable hydrogels as delivery systems for OA and RA.

A Mechanically Resilient Soft Hydrogel Improves Drug Delivery for Treating Post-Traumatic Osteoarthritis in Physically Active Joints

Intra-articular delivery of disease-modifying osteoarthritis drugs (DMOADs) is likely to be most effective in early post-traumatic osteoarthritis (PTOA) when symptoms are minimal and patients are physically active. DMOAD delivery systems therefore must withstand repeated mechanical loading without affecting the drug release kinetics. Although soft materials are preferred for DMOAD delivery, mechanical loading can compromise their structural integrity and disrupt drug release. Here, we report a mechanically resilient soft hydrogel that rapidly self-heals under conditions resembling human running while maintaining sustained release of the cathepsin-K inhibitor L-006235 used as a proof-of-concept DMOAD. Notably, this hydrogel outperformed a previously reported hydrogel designed for intra-articular drug delivery, used as a control in our study, which neither recovered nor maintained drug release under mechanical loading. Upon injection into mouse knee joints, the hydrogel showed consistent release kinetics of the encapsulated agent in both treadmill-running and non-running mice. In a mouse model of aggressive PTOA exacerbated by treadmill running, L-006235 hydrogel markedly reduced cartilage degeneration. To our knowledge, this is the first hydrogel proven to withstand human running conditions and enable sustained DMOAD delivery in physically active joints, and the first study demonstrating reduced disease progression in a severe PTOA model under rigorous physical activity, highlighting the hydrogel's potential for PTOA treatment in active patients.

Role of hydrogels in osteoarthritis: A comprehensive review

Osteoarthritis (OA) is a chronic, degenerative, and age-related disease. It is characterized by chronic inflammation, progressive articular cartilage destruction, and subchondral bone sclerosis. The current effective treatment for OA is limited. Hydrogel is a kind of unique carrier with well-known biocompatibility, softness, and high water content among various biomaterials. Hydrogels are developed for different biomedical applications, for instance, drug delivery, and tissue engineering. To date, a variety of hydrogels-based therapies have been used in OA patients or animal models. In this review, we comprehensively summarized the potential role of hydrogels in chondrocytes proliferation, apoptosis, and inflammatory component production and discussed the impact of hydrogels on OA development. The collection of this information will help better understand the present progress of hydrogels in OA.

In Situ Photo-crosslinkable Hyaluronic Acid/Gelatin Hydrogel for Local Nitric Oxide Delivery

An increasing number of studies have shown that the local release of nitric oxide (NO) from hydrogels stimulates tissue regeneration by modulating cell proliferation, angiogenesis, and inflammation. The potential biomedical uses of NO-releasing hydrogels can be expanded by enabling their application in a fluid state, followed by controlled gelation triggered by an external factor. In this study, we engineered a hydrogel composed of methacrylated hyaluronic acid (HAGMA) and thiolated gelatin (GELSH) with the capacity for in situ photo-cross-linking, coupled with localized NO release. To ensure a gradual and sustained NO release, we charged the hydrogels with poly(l-lactic-co-glycolic acid) (PLGA) nanoparticles functionalized with S-nitrosoglutathione (GSNO), safeguarding SNO group integrity during photo-cross-linking. The formation of thiol-ene bonds via the reaction between GELSH's thiol groups and HAGMA's vinyl groups substantially accelerated gelation (by a factor of 6) and increased the elastic modulus of hydrated hydrogels (by 1.9-2.4 times). HAGMA/GELSH hydrogels consistently released NO over a 14 day duration, with the release of NO depending on the hydrogels' equilibrium swelling degree, determined by the GELSH-to-HAGMA ratio. Biocompatibility assessments confirmed the suitability of these hydrogels for biological applications as they display low cytotoxicity and stimulated fibroblast adhesion and proliferation. In conclusion, in situ photo-cross-linkable HAGMA/GELSH hydrogels, loaded with PLGA-GSNO nanoparticles, present a promising avenue for achieving localized and sustained NO delivery in tissue regeneration applications.

Skin Cell and Tissue Responses to Cross-Linked Hyaluronic Acid in Low-Grade Inflammatory Conditions

Hyaluronic acid (HA), used in a variety of medical applications, is associated in rare instances to long-term adverse effects. Although the aetiology of these events is unknown, a number of hypotheses have been proposed, including low molecular weight of HA (LMW-HA) in the filler products. We hypothesized that cross-linked HA and its degradation products, in a low-grade inflammatory microenvironment, could impact immune responses that could affect cell behaviours in the dermis. Using two different cross-linking technologies VYC-15L and HYC-24L+, and their hyaluronidase-induced degradation products, we observed for nondegraded HA, VYC-15L and HYC-24L+, a moderate and transient increase in IL-1β, TNF-α in M1 macrophages under low-grade inflammatory conditions. Endothelial cells and fibroblasts were preconditioned using inflammatory medium produced by M1 macrophages. 24 h after LMW-HA fragments and HA stimulation, no cytokine was released in these preconditioned cells. To further characterize HA responses, we used a novel in vivo murine model exhibiting a systemic low-grade inflammatory phenotype. The intradermal injection of VYC-15L and its degradation products induced an inflammation and cell infiltration into the skin that was more pronounced than those by HYC-24L+. This acute cutaneous inflammation was likely due to mechanical effects due to filler injection and tissue integration rather than its biological effects on inflammation. VYC-15L and its degradation product potentiated microvascular response to acetylcholine in the presence of a low-grade inflammation. The different responses with 2D cell models and mouse model using the two tested cross-linking HA technologies showed the importance to use integrative complex model to better understand the effects of HA products according to inflammatory state.

Adhesive hydrogels in osteoarthritis: from design to application

Osteoarthritis (OA) is the most common type of degenerative joint disease which affects 7% of the global population and more than 500 million people worldwide. One research frontier is the development of hydrogels for OA treatment, which operate either as functional scaffolds of tissue engineering or as delivery vehicles of functional additives. Both approaches address the big challenge: establishing stable integration of such delivery systems or implants. Adhesive hydrogels provide possible solutions to this challenge. However, few studies have described the current advances in using adhesive hydrogel for OA treatment. This review summarizes the commonly used hydrogels with their adhesion mechanisms and components. Additionally, recognizing that OA is a complex disease involving different biological mechanisms, the bioactive therapeutic strategies are also presented. By presenting the adhesive hydrogels in an interdisciplinary way, including both the fields of chemistry and biology, this review will attempt to provide a comprehensive insight for designing novel bioadhesive systems for OA therapy.

Injectable Drug Delivery Systems for Osteoarthritis and Rheumatoid Arthritis

Joint diseases are one of the most common causes of morbidity and disability worldwide. The main diseases that affect joint cartilage are osteoarthritis and rheumatoid arthritis, which require chronic treatment focused on symptomatic relief. Conventional drugs administered through systemic or intra-articular routes have low accumulation and/or retention in articular cartilage, causing dose-limiting toxicities and reduced efficacy. Therefore, there is an urgent need to develop improved strategies for drug delivery, in particular, the use of micro- and nanotechnology-based methods. Encapsulation of therapeutic agents in delivery systems reduces drug efflux from the joint and protects against rapid cellular and enzymatic clearance following intra-articular injection. Consequently, the use of drug delivery systems decreases side effects and increases therapeutic efficacy due to enhanced drug retention in the intra-articular space. Additionally, the frequency of intra-articular administration is reduced, as delivery systems enable sustained drug release. This review summarizes various advanced drug delivery systems, such as nano- and microcarriers, developed for articular cartilage diseases.

Applications and prospects of intra-articular drug delivery system in arthritis therapeutics

Arthritis is a kind of chronic disease that affects joints and muscles with the symptoms of joint pain, inflammation and limited movement of joints. Among various clinical therapies, drug therapy has been extensively applied because of its accessibility, safety and effectiveness. In recent years, the intra-articular injection has dramatic therapeutic effects in treating arthritis with high patient compliance and low side effects. In this review, we will introduce pathology of arthritis, along with the accessible treatment and diagnosis methods, then we will summarize major advances of current hopeful intra-articular delivery systems such as microspheres, hydrogels, nanoparticles and liposomes. At last, some safety assessments in the preclinical work and the main challenges for the further development of intra-articular treatment were also discussed.

An optimal medicinal and edible Chinese herbal formula attenuates particulate matter-induced lung injury through its anti-oxidative, anti-inflammatory and anti-apoptosis activities

Objective

Identifying novel strategies to prevent particulate matter (PM)-induced lung injury is crucial for the reduction of the morbidity of chronic respiratory diseases. The combined intervention represented by herbal formulae for simultaneously targeting multiple pathological processes can provide a more beneficial effect than the single intervention. The aim of this paper is therefore to design a safe and effective medicinal and edible Chinese herbs (MECHs) formula against PM-induced lung injury.

Methods

PM-induced oxidative stress, inflammatory response and apoptosis A549 cell model were used to screen anti-oxidant, anti-inflammatory and anti-apoptotic MECHs, respectively. A network pharmacology method was utilized to rationally design a novel herbal formula. Ultra performance liquid chromatography-mass spectrometer was utilized to assess the quality control of MECHs formula. The excretion of magnetic iron oxide nanospheres of the MECHs formula was estimated in zebrafish. The MECH formula against PM-induced lung injury was investigated with mice experiments.

Results

Five selected herbs were rationally designed to form a new MECH formula, including Citri Exocarpium Rubrum (Juhong), Lablab Semen Album (Baibiandou), Atractylodis Macrocephalae Rhizoma (Baizhu), Mori Folium (Sangye) and Polygonati Odorati Rhizoma (Yuzhu). The formula effectively promoted the magnetic iron oxide nanospheres excretion in zebrafish. The mid/high dose formula significantly prevented PM-induced lung damage in mice by enhancing the activity of SOD and GSH-Px, reducing the MDA and ROS level and attenuating the upregulation of pro-inflammatory cytokine (IL-6, IL-8, IL-1β and TNF-α), down regulating the protein expression of NF-κB, STAT3 and Caspase-3.

Conclusion

Our findings suggest that the effective MECHs formula will become a novel strategy for preventing PM-induced lung injury and provide a paradigm for the development of functional foods using MECHs.

Gene Regulations upon Hydrogel-Mediated Drug Delivery Systems in Skin Cancers-An Overview

The incidence of skin cancer has increased dramatically in recent years, particularly in Caucasian populations. Specifically, the metastatic melanoma is one of the most aggressive cancers and is responsible for more than 80% of skin cancer deaths around the globe. Though there are many treatment techniques, and drugs have been used to cure this belligerent skin cancer, the side effects and reduced bioavailability of drug in the targeted area makes it difficult to eradicate. In addition, cellular metabolic pathways are controlled by the skin cancer driver genes, and mutations in these genes promote tumor progression. Consequently, the MAPK (RAS-RAF-MEK-ERK pathway), WNT and PI3K signaling pathways are found to be important molecular regulators in melanoma development. Even though hydrogels have turned out to be a promising drug delivery system in skin cancer treatment, the regulations at the molecular level have not been reported. Thus, we aimed to decipher the molecular pathways of hydrogel drug delivery systems for skin cancer in this review. Special attention has been paid to the hydrogel systems that deliver drugs to regulate MAPK, PI3K-AKT-mTOR, JAK-STAT and cGAS-STING pathways. These signaling pathways can be molecular drivers of skin cancers and possible potential targets for the further research on treatment of skin cancers.

The Role of Polymeric Biomaterials in the Treatment of Articular Osteoarthritis

Osteoarthritis is a high-prevalence joint disease characterized by the degradation of cartilage, subchondral bone thickening, and synovitis. Due to the inability of cartilage to self-repair, regenerative medicine strategies have become highly relevant in the management of osteoarthritis. Despite the great advances in medical and pharmaceutical sciences, current therapies stay unfulfilled, due to the inability of cartilage to repair itself. Additionally, the multifactorial etiology of the disease, including endogenous genetic dysfunctions and exogenous factors in many cases, also limits the formation of new cartilage extracellular matrix or impairs the regular recruiting of chondroprogenitor cells. Hence, current strategies for osteoarthritis management involve not only analgesics, anti-inflammatory drugs, and/or viscosupplementation but also polymeric biomaterials that are able to drive native cells to heal and repair the damaged cartilage. This review updates the most relevant research on osteoarthritis management that employs polymeric biomaterials capable of restoring the viscoelastic properties of cartilage, reducing the symptomatology, and favoring adequate cartilage regeneration properties.

Local retention efficacy of steroid-loaded PLGA microspheres in epidural injection

Long-term effects of epidural steroid injections for pain management require novel drug formulations that increase tissue retention time. Present study aimed to investigate the local retention of steroid-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres in epidural injection using a rabbit model. Twenty rabbits were randomly assigned to a PLGA group (n = 10) and a triamcinolone acetonide (TA) group (n = 10). Each animal was injected with either TA-loaded PLGA microspheres or conventional TA suspension into the lumbar epidural space. The lumbar segments were then harvested from the sacrificed rabbits on day 1, week 1, 2, and 4 after the injection. On day 1, the residual steroid concentration (RSC) was lower in the PLGA group than in the TA group (5.03 ppm vs. 13.01 ppm). However, after a week, more steroids remained in the PLGA group (3.29 ppm vs. 0.58 ppm). After 2 weeks, fewer steroids remained in the PLGA group than in the TA group, although both contained less than 10% of the initial retention dose. This study shows that steroid-loaded PLGA tended to have higher steroid retention in tissue than the steroid itself at the first week after epidural injection. However, most of the steroids disappeared after 2 weeks in both groups.

Dexamethasone: Insights into Pharmacological Aspects, Therapeutic Mechanisms, and Delivery Systems

Dexamethasone (DEX) has been widely used to treat a variety of diseases, including autoimmune diseases, allergies, ocular disorders, cancer, and, more recently, COVID-19. However, DEX usage is often restricted in the clinic due to its poor water solubility. When administered through a systemic route, it can elicit severe side effects, such as hypertension, peptic ulcers, hyperglycemia, and hydro-electrolytic disorders. There is currently much interest in developing efficient DEX-loaded nanoformulations that ameliorate adverse disease effects inhibiting advancements in scientific research. Various nanoparticles have been developed to selectively deliver drugs without destroying healthy cells or organs in recent years. In the present review, we have summarized some of the most attractive applications of DEX-loaded delivery systems, including liposomes, polymers, hydrogels, nanofibers, silica, calcium phosphate, and hydroxyapatite. This review provides our readers with a broad spectrum of nanomedicine approaches to deliver DEX safely.

Management of osteoarthritis: From drug molecules to nano/micromedicines

With the change in lifestyle and aging of the population, osteoarthritis (OA) is emerging as a major medical burden globally. OA is a chronic inflammatory and degenerative disease initially manifesting with joint pain and eventually leading to permanent disability. To date, there are no drugs available for the definitive treatment of osteoarthritis and most therapies have been palliative in nature by alleviating symptoms rather than curing the disease. This coupled with the vague understanding of the early symptoms and methods of diagnosis so that the disease continues as a global problem and calls for concerted research efforts. A cascade of events regulates the onset and progression of osteoarthritis starting with the production of proinflammatory cytokines, including interleukin (IL)‐1β, IL‐6, tumor necrosis factor (TNF)‐α; catabolic enzymes, such as matrix metalloproteinases (MMPs)‐1, ‐3, and ‐13, culminating into cartilage breakdown, loss of lubrication, pain, and inability to load the joint. Although intra‐articular injections of small and macromolecules are often prescribed to alleviate symptoms, low residence times within the synovial cavity severely impair their efficacy. This review will briefly describe the factors dictating the onset and progression of the disease, present the current clinically approved methods for its treatment and diagnosis, and finally elaborate on the main challenges and opportunities for the application of nano/micromedicines in the treatment of osteoarthritis. Thus, future treatment regimens will benefit from simultaneous consideration of the mechanobiological, the inflammatory, and tissue degradation aspects of the disease.

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement

Synovial and cartilage responsiveness to peri-operative hyaluronic acid ± dexamethasone administration following a limited injury to the rabbit stifle joint

Posttraumatic osteoarthritis (PTOA) can develop after an injury to the knee. Previous studies have indicated that an intra-articular (IA) injection of the potent glucocorticoid dexamethasone (DEX) may significantly prevent induction of PTOA. The aim of the present study was to investigate the effectiveness of a single IA injection of hyaluronic acid (HA), alone and in combination with DEX following a localized intra-articular injury as a PTOA-preventing treatment option. An established rabbit model of surgical injury consisting of dual intra-articular (IA) drill holes in a non-cartilaginous area of the femoral notch near the origin of the anterior cruciate ligament (ACL) to allow for bleeding into the joint space was used. Immediately following surgery, subjects were treated with HA, HA + DEX, or received no treatment. An uninjured control group was used for comparison (N = 5/group). Rabbits were sacrificed and investigated at 9 weeks post-injury. At 9 weeks post-injury, there was a significant protective capacity of the single IA treatment of DEX + HA on the histological grade of the synovial tissue, and some variable location-specific effects of HA alone and HA + DEX interactions on cartilage damage. Thus, it is possible that co-treatment with HA may interfere with the effectiveness of the DEX. In vitro friction testing indicated that DEX did not interfere with the lubricating ability of HA or synovial fluid on cartilage. These results suggest that a single IA administration of HA in combination with DEX following an IA injury is not recommended for inhibition of PTOA progression in this model.

Chitosan/Pluronic F127 Thermosensitive Hydrogel as an Injectable Dexamethasone Delivery Carrier

Intra-articular administration of anti-inflammatory drugs is a strategy that allows localized action on damaged articular cartilage and reduces the side effects associated with systemic drug administration. The objective of this work is to prepare injectable thermosensitive hydrogels for the long-term application of dexamethasone. The hydrogels were prepared by mixing chitosan (CS) and Pluronic-F127 (PF) physically. In addition, tripolyphosphate (TPP) was used as a crosslinking agent. Chitosan added to the mix increased the gel time compared to the pluronic gel alone. The incorporation of TPP into the material modified the morphology of the hydrogels formed. Subsequently, MTS and Live/Dead® experiments were performed to investigate the toxicity of hydrogels against human chondrocytes. The in vitro releases of dexamethasone (DMT) from CS-PF and CS-PF-TPP gels had an initial burst and took more time than that from the PF hydrogel. In vivo studies showed that hydrogels retained the fluorescent compound longer in the joint than when administered in PBS alone. These results suggest that the CS-PF and CS-PF-TPP hydrogels loaded with DMT could be a promising drug delivery platform for the treatment of osteoarthritis.

Supercritical carbon dioxide decellularized porcine cartilage graft with PRP attenuated OA progression and regenerated articular cartilage in ACLT-induced OA rats

Knee osteoarthritis (OA) is a common degenerative articular disorder and considered one of the primary causes of pain and functional disability. Knee OA is prevalent in 10% of men and 13% of women aged 60 years above. The study aims to use cartilage tissue engineering that combines the triads of decellularized porcine cartilage graft as "scaffold," plasma rich platelet (PRP) as "signal" and chondrocytes from rat as "cell" to attenuate ACLT-induced OA progression and regenerate the knee cartilage in rats. Decellularization of the porcine cartilage was characterized by hematoxylin and eosin, 4,6-Diamidino-2-phenylindole staining, scanning electron microscopy and residual DNA quantification. The protective effect of decellularized porcine cartilage graft (dPCG) was evaluated by intra-articular administration in surgically induced anterior cruciate ligament transection (ACLT) rat osteoarthritis (OA) model. Supercritical carbon dioxide technology completely decellularized the porcine cartilage. Intra-articular administration of dPCG with or without PRP significantly reduced the ACLT-induced OA symptoms and attenuated the OA progression. Pain-relief by dPCG with or without PRP was assessed by capacitance meter and improved articular cartilage damage in the rat knee was characterized by X-ray and micro-CT. Besides, the histological analysis depicted cartilage protection by dPCG with or without PRP. The repairation and attenuation effect by dPCG with or without PRP in the articular knee cartilage damage were also explored by safranin-O, type II collagen, aggrecan and SOX-9 immuno-staining. To conclude, intra-articular administration of dPCG with or without PRP is efficient in repairing the damaged cartilage in the experimental OA model.

Dexamethasone-loaded thermo-sensitive hydrogel attenuates osteoarthritis by protecting cartilage and providing effective pain relief

Background

We utilized the destabilization of medial meniscus (DMM)-induced mice to illustrate the osteoarthritis (OA) suppressing and pain-relieving effects of a novel prolonged-release intra-articular (IA)-dexamethasone-loaded thermo-sensitive hydrogel (DLTH).

Methods

The effects of temperature and pH on DLTH formation and in vitro DLTH release profile were assessed. C57BL/6J mice were randomly divided into three groups: Ctrl group, Model group and DLTH group. The DLTH group received joint injections of 10 µL DLTH (1 mg/kg) into the right knee once a week from week 2 to week 11. We performed micro-computed tomography (Micro-CT) and histological analyses of safranin O-fast green, hematoxylin and eosin, and tartrate-resistant acid phosphatase in knee joints. We also carried out immunohistochemical (IHC) staining for matrix metalloproteinase-9 (MMP-9), MMP-13, and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5) in cartilage and Ki-67 in synovia. Pain behavioral testing was carried out in all mice. The serum content of prostaglandin E2 (PGE2) and real-time polymerase chain reaction (PCR) of inflammatory cytokines and pain-related factors in dorsal root ganglia (DRGs) were evaluated.

Results

It took 20 minutes to form DLTH at pH 7.0 and 37 °C. The cumulative release profiles of dexamethasone (Dex) from DLTH at 37 °C revealed a rapid release in the first 24 h and a sustained slow release for 7 days. In vivo study illustrated that DLTH attenuated OA bone destruction and ameliorated synovitis and progression of OA in DMM-induced mice. The chondroprotective effects of DLTH were mediated by decreased expressions of MMP-9, MMP-13, and ADAMTS-5. The results showed that IA-DLTH exerted pain-relieving effects in OA mice. Upregulation of nociceptive response time (NRT) and downregulations of serum PGE2, inflammatory factors, and pain-related mediators in DRGs of mice in the DLTH group were recorded.

Conclusions

Data presented in this study elucidated that DLTH exhibited a long and lasting Dex release and it is a potential sustainable drug delivery system (DDS) to treat OA locally. IA-DLTH injection exerted chondroprotective and pain-relieving effects in DMM-induced arthritis. The involvement of MMP-9, MMP-13, ADAMTS-5, and inflammatory and pain-related factors, may account for the suppression of OA progression and pain.

Oxi-HA/ADH Hydrogels: A Novel Approach in Tissue Engineering and Regenerative Medicine

Hyaluronic acid (HA) is a natural polyelectrolyte abundant in mammalian connective tissues, such as cartilage and skin. Both endogenous and exogenous HA produced by fermentation have similar physicochemical, rheological, and biological properties, leading to medical and dermo-cosmetic products. Chemical modifications such as cross-linking or conjugation in target groups of the HA molecule improve its properties and in vivo stability, expanding its applications. Currently, HA-based scaffolds and matrices are of great interest in tissue engineering and regenerative medicine. However, the partial oxidation of the proximal hydroxyl groups in HA to electrophilic aldehydes mediated by periodate is still rarely investigated. The introduced aldehyde groups in the HA backbone allow spontaneous cross-linking with adipic dihydrazide (ADH), thermosensitivity, and noncytotoxicity to the hydrogels, which are advantageous for medical applications. This review provides an overview of the physicochemical properties of HA and its usual chemical modifications to better understand oxi-HA/ADH hydrogels, their functional properties modulated by the oxidation degree and ADH concentration, and the current clinical research. Finally, it discusses the development of biomaterials based on oxi-HA/ADH as a novel approach in tissue engineering and regenerative medicine.

Effects of Streptococcus thermophilus on anterior cruciate ligament transection-induced early osteoarthritis in rats

Osteoarthritis (OA) is the most common joint disorder and is classically defined as a progressively degenerative disease of articular cartilage. It manifests as joint pain and disability and currently has no comprehensive treatments. The primary purpose of the present study was to test the effects of probiotics, Streptococcus thermophilus (TCI633), on anterior cruciate ligament transection (ACLT)-induced experimental osteoarthritis (OA) in rats. In the current study, the experimental groups were given TCI633 (5x10⁹, 5x10¹⁰ and 5x10¹¹ CFU/kg/day) and glucosamine sulfate (250 mg/kg) between week 8 and 20 following ACLT. The results showed that oral administration of TCI633 and glucosamine had significant therapeutic effects on pain behaviors and knee swelling. Dose-dependent effects of TCI633 were also observed in ACLT-treated rats. Histopathological analysis demonstrated that ACLT+TCI633 (5x10⁹, 5x10¹⁰ and 5x10¹¹ CFU/kg/day) improved the synovial inflammation and cartilage damage of ACLT rats. Histology evaluation using the Osteoarthritis Research Society International system and synovial inflammatory score analysis showed the dose-dependent inhibition of TCI633 on synovial inflammation and cartilage damage. Immunohistochemical staining and TUNEL apoptosis staining showed that TCI633 could effectively increase the expression of type II collagen and reduce the amount of chondrocyte apoptosis in cartilage. Therefore, the present study demonstrated that oral intake of TCI633 could significantly suppressing pain behavior, reduce joint swelling and synovial tissue inflammation and increase type II collagen expression in cartilage. There was also a reduction in chondrocyte apoptosis and decreased progression of OA in ACLT-treated rats.

Osteoarthritis In Vitro Models: Applications and Implications in Development of Intra-Articular Drug Delivery Systems

Osteoarthritis (OA) is a complex multi-target disease with an unmet medical need for the development of therapies that slow and potentially revert disease progression. Intra-articular (IA) delivery has seen a surge in osteoarthritis research in recent years. As local administration of molecules, this represents a way to circumvent systemic drug delivery struggles. When developing intra-articular formulations, the main goals are a sustained and controlled release of therapeutic drug doses, taking into account carrier choice, drug molecule, and articular joint tissue target. Therefore, the selection of models is critical when developing local administration formulation in terms of accurate outcome assessment, target and off-target effects and relevant translation to in vivo. The current review highlights the applications of OA in vitro models in the development of IA formulation by means of exploring their advantages and disadvantages. In vitro models are essential in studies of OA molecular pathways, understanding drug and target interactions, assessing cytotoxicity of carriers and drug molecules, and predicting in vivo behaviors. However, further understanding of molecular and tissue-specific intricacies of cellular models for 2D and 3D needs improvement to accurately portray in vivo conditions.

Recent Advances in Clinical Translation of Intra-Articular Osteoarthritis Drug Delivery Systems

Osteoarthritis (OA) is a degenerative disease of the joints and a leading cause of physical disability in adults. Intra-articular (IA) therapy is a popular treatment strategy for localized, single-joint OA; however, small-molecule drugs such as corticosteroids do not provide prolonged relief. One possible reason for their lack of efficacy is high clearance rates from the joint through constant lymphatic drainage of the synovial tissues and synovial fluid and also by their exchange via the synovial vasculature. Advanced drug delivery strategies for extended release of therapeutic agents in the joint space is a promising approach to improve outcomes for OA patients. Broadly, the basic principle behind this strategy is to encapsulate therapeutic agents in a polymeric drug delivery system (DDS) for diffusion- and/or degradation-controlled release, whereby degradation can occur by hydrolysis or tied to relevant microenvironmental cues such as pH, reactive oxygen species (ROS), and protease activity. In this review, we highlight the development of clinically tested IA therapies for OA and highlight recent systems which have been investigated preclinically. DDS strategies including hydrogels, liposomes, polymeric microparticles (MPs) and nanoparticles (NPs), drug conjugates, and combination systems are introduced and evaluated for clinical translational potential.

Cartilage tissue engineering for obesity-induced osteoarthritis: Physiology, challenges, and future prospects

Osteoarthritis (OA) is a multifactorial joint disease with pathological changes that affect whole joint tissue. Obesity is acknowledged as the most influential risk factor for both the initiation and progression of OA in weight-bearing and non-weight-bearing joints. Obesity-induced OA is a newly defined phenotypic group in which chronic low-grade inflammation has a central role. Aside from persistent chronic inflammation, abnormal mechanical loading due to increased body weight on weight-bearing joints is accountable for the initiation and progression of obesity-induced OA. The current therapeutic approaches for OA are still evolving. Tissue-engineering-based strategy for cartilage regeneration is one of the most promising treatment breakthroughs in recent years. However, patients with obesity-induced OA are often excluded from cartilage repair attempts due to the abnormal mechanical demands, altered biomechanical and biochemical activities of cells, persistent chronic inflammation, and other obesity-associated factors. With the alarming increase in the number of obese populations globally, the need for an innovative therapeutic approach that could effectively repair and restore the damaged synovial joints is of significant importance for this sub-population of patients. In this review, we discuss the involvement of the systemic and localized inflammatory response in obesity-induced OA and the impact of altered mechanical loading on pathological changes in the synovial joint. Moreover, we examine the current strategies in cartilage tissue engineering and address the critical challenges of cell-based therapies for OA. Besides, we provide examples of innovative ways and potential strategies to overcome the obstacles in the treatment of obesity-induced OA.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Altogether, this review delivers insight into obesity-induced OA and offers future research direction on the creation of tissue engineering-based therapies for obesity-induced OA.

Temporomandibular joint injections in dogs with temporomandibular joint pain: 11 cases (2015-2019)

OBJECTIVES

To describe and evaluate the clinical application of temporomandibular joint injections using betamethasone and ropivacaine in German Shepherd dogs suffering from non-odontogenic orofacial pain due to temporomandibular dysplasia and/or osteoarthritis.

MATERIALS AND METHODS

Outcomes in dogs presented with clinical signs of non-odontogenic orofacial pain associated to temporomandibular joint dysplasia and/or arthritis and treated with a temporomandibular joint injection were retrospectively-prospectively evaluated.

RESULTS

The overall clinical signs free period ranged between 25 to 1579 days, with an average of 461 days. The clinical signs free period for temporomandibular joint osteoarthritis scores 1, 2 and 3 were on average 659 days (180-1579 days), 134 days (42-355 days) and 723 days (25-1377 days), respectively. Similarly the temporomandibular dysplasia scores 1, 2 and 3 were on average 306 days (26-1579 days), 1377 days and 669 days (25-1429 days) respectively. Those dogs in which only one side was injected the clinical signs free period average was 639 days (25-1578 days), compared with dogs in which both temporomandibular joints were injected showing a clinical signs free period average of 378 days (42-1377 days).

CLINICAL SIGNIFICANCE

The temporomandibular joint injection technique proved to be feasible with a decent outcome in dogs suffering from non-odontogenic orofacial pain associated with temporomandibular joint osteoarthritis and/or dysplasia. Further randomised studies are required to confirm the effectiveness of this intervention.

The perspectives of intra-articular therapy in the management of osteoarthritis

Management of Osteoarthritis (OA) still is a challenge for clinicians. Taking into account a multidisciplinary approach including pharmacological and non-pharmacological treatments, intra-articular (IA) injection could be considered as an effective local therapy. Areas covered This review provides a new perspective of IA treatment going beyond current available IA agents. We describe novel biological targets for developing new IA agents and innovative modalities of delivery systems. Additional topics include predictors of response for a better choice of IA agents for each patient, diagnostic and prognostic role of biomarkers, accuracy of IA injection, and cost-effectiveness of IA injection. Expert opinion IA treatments seem to be very promising for the management of OA. Identifying clinical and biochemical predictive factors could drive clinician to the appropriate therapeutic approach. To date, there is a gap regarding the benefit of IA treatments in the 'real practice' once they have been adopted. However, considering these promising effects of IA approach, several open questions remain not clarified.

Histone deacetylase 4 deletion results in abnormal chondrocyte hypertrophy and premature ossification from collagen type 2α1‑expressing cells

Histone deacetylase 4 (HDAC4) plays a vital role in chondrocyte hypertrophy and bone formation. To investigate the function of HDAC4 in postnatal skeletal development, the present study developed lineage‑specific HDAC4‑knockout mice [collagen type 2α1 (Col2α1)‑Cre, HDAC4d/d mice] by crossing transgenic mice expressing Cre recombinase. Thus, a specific ablation of HDAC4 was performed in Col2α1‑expressing mice cells. The knee joints of HDAC4fl/fl and Col2α1‑Cre, HDAC4d/d mice were analyzed at postnatal day (P)2‑P21 using an in vivo bromodeoxyuridine (BrdU) assay, and Safranin O, Von Kossa and whole‑body staining were used to evaluate the developmental growth plate, hypertrophic differentiation, mineralization and skeletal mineralization patterns. The trabecular bone was analyzed using microcomputed tomography. The expressions of BrdU, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)‑13, runt‑related transcription factor (Runx)‑2, osteoprotegerin (OPG), CD34, type X collagen (ColX), osteocalcin and Wnt5a were determined using immunohistochemistry, in situ hybridization (ISH) and reverse transcription‑quantitative (RT‑q)PCR. The results demonstrated that HDAC4‑null mice (HDAC4d/d mice) were severely runted; these mice had a shortened hypertrophic zone (histopathological evaluation), accelerated vascular invasion and articular mineralization (Von Kossa staining), elevated expressions of MMP‑13, Runx2, OPG and CD34 (RT‑qPCR and immunohistochemistry), downregulated expression of the proliferative marker BrdU and PCNA (immunohistochemistry), increased expression of ColX and decreased expression of Wnt5a (ISH). In conclusion, chondrocyte‑derived HDAC4 was responsible for regulating chondrocyte proliferation and differentiation as well as endochondral bone formation.

Inflammation-Modulating Hydrogels for Osteoarthritis Cartilage Tissue Engineering

Osteoarthritis (OA) is the most common form of the joint disease associated with age, obesity, and traumatic injury. It is a disabling degenerative disease that affects synovial joints and leads to cartilage deterioration. Despite the prevalence of this disease, the understanding of OA pathophysiology is still incomplete. However, the onset and progression of OA are heavily associated with the inflammation of the joint. Therefore, studies on OA treatment have sought to intra-articularly deliver anti-inflammatory drugs, proteins, genes, or cells to locally control inflammation in OA joints. These therapeutics have been delivered alone or increasingly, in delivery vehicles for sustained release. The use of hydrogels in OA treatment can extend beyond the delivery of anti-inflammatory components to have inherent immunomodulatory function via regulating immune cell polarization and activity. Currently, such immunomodulatory biomaterials are being developed for other applications, which can be translated into OA therapy. Moreover, anabolic and proliferative levels of OA chondrocytes are low, except initially, when chondrocytes temporarily increase anabolism and proliferation in response to structural changes in their extracellular environment. Therefore, treatments need to restore matrix protein synthesis and proliferation to healthy levels to reverse OA-induced damage. In conjugation with injectable and/or adhesive hydrogels that promote cartilage tissue regeneration, immunomodulatory tissue engineering solutions will have robust potential in OA treatment. This review describes the disease, its current and future immunomodulatory therapies as well as cartilage-regenerative injectable and adhesive hydrogels.

Protocatechuic acid attenuates anterior cruciate ligament transection-induced osteoarthritis by suppressing osteoclastogenesis

Osteoarthritis (OA) is related to over-proliferation or differentiation of osteoclasts. Although protocatechuic acid (PCA) has been identified to inhibit osteoclast differentiation and stimulate apoptosis in mature osteoclasts, whether it can relieve OA is still unknown. The present study aimed to investigate the effect of PCA on anterior cruciate ligament transection (ACLT)-induced OA and the potential mechanisms of action behind this effect. ACLT was performed on rats, which were then treated with or without PCA. C-terminal telopeptide of type I collagen (CTX-I) and CTX-II were tested in knee joint protein extracts by ELISA. Damage to cartilage was evaluated using Safranin-O/Fast Green staining. Osteoclast-related gene and protein expression was assessed through reverse transcription-quantitative PCR and western blotting. Tartrate-resistant acid phosphatase (TRAP) staining and functional bone resorption pit assays were performed using RAW264.7 murine macrophage cells to determine the effects of PCA on osteoclastic formation and function, respectively, in vitro. Finally, the activity of osteoclastogenesis-related signaling pathways was evaluated by western blotting. Levels of CTX-II were relatively decreased and Safranin-O/fast green staining indicated milder changes in the articular cartilage in the PCA treatment group. PCA downregulated osteoclast specific markers and suppressed receptor activator of nuclear factor-κB ligand-induced formation of TRAP-positive multinucleated cells, bone-resorption and pit formation. Mitogen-activated protein kinase (MAPK) and Akt signaling as well as the downstream factors, were downregulated by PCA. In conclusion, the present study demonstrated that PCA attenuated ACLT-induced OA by suppressing osteoclastogenesis by inhibiting the MAPK, ATK and NF-κB signaling pathways.

Stabilized Loading of Hyaluronic Acid-Containing Hydrogels into Magnesium-Based Cannulated Screws

Cannulated screws have a structure for inserting a guide wire inside them to effectively correct complicated fractures. Magnesium, an absorbable metal used to manufacture cannulated screws, may decompose in the body after a certain period of implantation. The hydrogel formed by hyaluronic acid (HA) and polygalacturonic acid (PGA) has been used into Mg-based cannulated screws to prevent bone resorption owing to the rapid corrosion of Mg with unfavorable mechanical properties and a high ambient pH. In addition, Ca ions were added to the gel for cross-linking the carboxyl groups to modify the gelation rate and physical properties of the gel. The developed hydrogels were injected into the Mg-based cannulated screws, after which they released HA and Ca. The possibility of the application of this system as a cannulated screw was evaluated based on the corrosion resistance, gel degradation rate, HA release, toxicity toward osteocytes, and experiments involving the implantation of the screws into the femurs of rats. Ca ions first bound to PGA and delayed the gelation time and dissolution rate. However, they interfered with HA binding and increased the elution of HA at the beginning of gel degradation. Ca(NO₃)₂ concentrations higher than 0.01 M and low pH environments inhibited osteoblast differentiation and proliferation, owing to the elution of HA from the hydrogel. On the other hand, when the HA hydrogel with a proper amount of Ca was inserted into a magnesium screw, the degradation of Mg was delayed, and the presence of the gel contributed to new bone formation and osteocyte expansion.

Thermoresponsive Hyalomer intra-articular hydrogels improve monoiodoacetate-induced osteoarthritis in rats

Osteoarthritis (OA) is characterized by degenerative knees, fingers and hip joints. In OA joints, the concentration and polymerization of hyaluronic acid (HA) are changed; affecting the viscosity of the synovial fluid. Replenishing HA synovial fluid content, along with an anti-inflammatory drug could be a cost-effective strategy. As free drugs are rapidly cleared out of the synovial fluid, we aimed to prepare Hyalomer in situ forming gel for intra-articular (IA) injection. Hyalomer contains poloxamer 407 (PX) as thermogelling agent, HA, and diclofenac potassium (DK) as an anti-inflammatory. Hyalomer formulations were prepared and characterized in terms of sol-gel transition, gelation time, in vitro release and 3-month stability. The selected Hyalomer formula was injected IA in OA rat model, in comparison to its individual components. The optimized Hyalomer formulation showed 25% DK release after 24 h and 40% after 4 days. The gelation time was 40 ± 2.08 s and gelation temperature was 26 ± 1.87 °C. Hyalomer maintained the percentage drug release and DK content after 3-months storage. In OA rats, Hyalomer showed the highest anti-nociceptive and anti-edematous effect. Both radiography and histopathology revealed regenerated cartilage profile in Hyalomer-treated group. combining IA HA and diclofenac in thermoresponsive gel represents a promising therapeutic alternative for OA.

Design and In Vivo Pharmacokinetic Evaluation of Triamcinolone Acetonide Microcrystals-Loaded PLGA Microsphere for Increased Drug Retention in Knees after Intra-Articular Injection

A novel polymeric microsphere (MS) containing micronized triamcinolone acetonide (TA) in a crystalline state was structured to provide extended drug retention in joints after intra-articular (IA) injection. Microcrystals with a median diameter of 1.7 μm were prepared by ultra-sonication method, and incorporated into poly(lactic-co-glycolic acid)/poly(lactic acid) (PLGA/PLA) MSs using spray-drying technique. Cross-sectional observation and X-ray diffraction analysis showed that drug microcrystals were evenly embedded in the MSs, with a distinctive crystalline nature of TA. In vitro drug release from the novel MSs was markedly decelerated compared to those from the marketed crystalline suspension (Triam inj.^®), or even 7.2 μm-sized TA crystals-loaded MSs. The novel system offered prolonged drug retention in rat joints, providing quantifiable TA remains over 28 days. Whereas, over 95% of IA TA was removed from joints within seven days, after injection of the marketed product. Systemic exposure of the steroidal compound was drastically decreased with the MSs, with <50% systemic exposure compared to that with the marketed product. The novel MS was physicochemically stable, with no changes in drug crystallinity and release profile over 12 months. Therefore, the TA microcrystals-loaded MS is expected to be beneficial in patients especially with osteoarthritis, with reduced IA dosing frequency.

Effect of intra-articular hyaluronan injection on inflammation and bone remodeling in the epiphyses and metaphyses of the knee in a murine model of joint injury

The TTR (transforming growth factor β1 (TGFβ1) injection with treadmill running) model of murine joint injury was used to examine effects of intra-articular Hyaluronan (IA HA) on the metabolism of subchondral bone. HA was injected 24 h after TGFβ1 injection and its effects on the mRNA of 80 genes in the Nfkb pathway, and bone remodeling genes, Acp5, Nos2 and Arg1, in femoral and tibial epiphyses/metaphyses of injected and contralateral legs was assessed. Structural bone parameters at those sites were determined by Micro-computed tomography (micro CT) and bone remodeling cells identified with histochemistry for tartrate-resistant acid phosphatase and immunohistochemistry for Nitric oxide synthase 2 (NOS2) and Arginase 1. Gene expression responses in femoral compartments were generally inhibitory and notably biphasic whereas the tibia was relatively non-responsive. Gene expression was also altered in the contralateral femoral compartment but were predominantly activated. IA TGFb did not alter bone structure in the injected leg, but resulted in a statistically significant reduction (25-40%) in trabecular bone of the contralateral limb. IA HA did not affect such changes. This bone loss was associated with an acute decrease in transcript abundance for Acp5, Nos2, Arg1 and this decrease persisted for Nos2 and Arg1. In conclusion, the data illustrate that in this model, IA TGFβ1 injection results in marked biphasic changes in NfKb-regulated apoptosis, IL1 and IL12 pathways, which were transiently altered after IA HA therapy. The finding that all modulations are essentially restricted to the femoral compartment is consistent with the predominant localization and clearance of injected HA from this site.

Active viscosupplements for osteoarthritis treatment

OBJECTIVE

Osteoarthritis is a chronic, painful and disabling disease which prevalence is increasing in developing countries. Patients with osteoarthritis present a reduced synovial fluid viscoelasticity due to a reduction in concentration and molecular weight of hyaluronic acid. Currently, the main treatment used to restore the compromised rheological properties of synovial fluid is the viscosupplementation by hyaluronic acid injections that can be combined with oral anti-inflammatory drugs for pain relief. Combination of viscosupplements with chemical agents or drugs is emerging as a new strategy to provide a double action of synovial fluid viscoelasticity recovery and the therapeutic effect of the bioactive principle.

METHODS

In this review, we present the latest research on the combination of viscosupplements with active molecules. We conducted a literature review of articles published in different web search engines and categorized according to the active molecule introduced into the viscosupplement.

RESULTS

Generally, the introduction of anti-inflammatory molecules have shown to improve pain relief although some cytotoxicity has been demonstrated especially for non-steroidal anti-inflammatory drugs. Other molecules such as antioxidant or disease modifying osteoarthritis drugs have been reported to improve viscosupplementation action. Drug delivery systems combined with hyaluronic acid could enhance the activity of the encapsulated molecules and provide better control over the drug release. Finally, biological approaches such as the use of stem cells or platelet-rich plasma seem to be the most promising strategies for cartilage recovery.

CONCLUSIONS

Combination therapy of viscosupplements with therapeutic agents, drug delivery systems or regenerative therapies can improve viscosupplementation outcome in terms of pain relief and joint functionality. However, further research is needed in order to reach more conclusive results.

Local Effects Following Single and Repeat Intra-Articular Injections of Triamcinolone Acetonide Extended-Release: Results from Three Nonclinical Toxicity Studies in Dogs

Introduction

Single intra-articular (IA) injections of poly(lactic-co-glycolic acid) (PLGA) microsphere-based triamcinolone acetonide extended-release (TA–ER; formerly FX006) demonstrated sustained, clinically relevant benefits in patients with knee osteoarthritis. The local effects of TA–ER were assessed in normal canine knees in three nonclinical studies.

Methods

Knees were evaluated for up to 6 weeks or 9 months after a single injection of TA–ER (2.1/6.25/18.75 mg TA), or TA crystalline suspension (TAcs, 18.75 mg TA), and for up to 6 months after three injections (every 1 or 3 months) of TA–ER (6.25/18.75 mg TA) or TAcs (18.75 mg). Vehicle-diluent, blank microspheres, and untreated knees were used as controls. Plasma and synovial fluid (SF) TA concentrations and standard histopathological assessment of the synovium were conducted. Articular cartilage morphology was assessed via modified Mankin scoring.

Results

Plasma and SF concentrations indicated prolonged dose-dependent TA joint residency with TA–ER compared with TAcs. Effects in articular cartilage were dose- and time-dependent and consistent with known effects of corticosteroids in the normal knee. Loss of Safranin O staining occurred, indicative of a reduction in cartilage matrix proteoglycan, and recovered in a similar manner for TA–ER and TAcs across all studies. Structural lesions were infrequent and generally comparable in severity between TA–ER and TAcs but slightly higher in incidence for TA–ER. Focal/multifocal foreign-body responses (FBR) to PLGA were observed in the superficial layer of the synovium, peaking after 4–6 weeks, with significant recovery or complete resolution by month 6.

Conclusions

These findings suggest that the effects of IA injections of TA–ER on cartilage are predominantly transient, and comparable to those observed with TAcs in the normal canine knee joint. These mild effects in the normal joint differ from the beneficial effects observed with TA–ER and other corticosteroids in disease models. The synovial FBR to PLGA microspheres was focal and transient.

Funding

Flexion Therapeutics, Inc.

Plain Language Summary

Plain language summary available for this article.

Electronic supplementary material

The online version of this article (10.1007/s40744-018-0125-3) contains supplementary material, which is available to authorized users.

Intra-Articular Formulation of GE11-PLGA Conjugate-Based NPs for Dexamethasone Selective Targeting-In Vitro Evaluation

Selectively targeted nanoscale drug delivery systems have recently emerged as promising intravenously therapeutic option for most chronic joint diseases. Here, a newly synthetized dodecapeptide (GE11)-polylactide-co-glycolide (PLGA)-based conjugate was used to prepare smart nanoparticles (NPs) intended for intra-articular administration and for selectively targeting Epidermal Growth Factor Receptor (EGFR). GE11-PLGA conjugate-based NPs are specifically uptaken by EGFR-overexpressed fibroblast; such as synoviocytes; which are the primarily cellular component involved in the development of destructive joint inflammation. The selective uptake could help to tune drug effectiveness in joints and to decrease local and systemic side effects. Dexamethasone (DXM) is a glucorticoid drug commonly used in joint disease treatment for both systemic and local administration route. In the present research; DXM was efficiently loaded into GE11-PLGA conjugate-based NPs through an eco-friendly nanoprecipitation method set up for this purpose. DXM loaded GE11-PLGA conjugate-based NPs revealed satisfactory ex vivo cytocompatibility; with proper size (≤150 nm) and good dimensional stability in synovial fluid. Intra-articular formulation was developed embedding DXM loaded GE11-PLGA conjugate-based NPs into thermosetting chitosan-based hydrogel; forming a biocompatible composite hydrogel able to quickly turn from liquid state into gel state at physiological temperature; within 15 min. Moreover; the use of thermosetting chitosan-based hydrogel extends the local release of active agent; DXM.

Injectable liquid polymers extend the delivery of corticosteroids for the treatment of osteoarthritis

Drug delivery strategies generally use inert materials, such as high molecular weight polymers, to encapsulate and control the release rate of therapeutic drugs. Diffusion governs release and depends on the ease of permeation of the polymer alongside the device thickness. Yet in applications such as osteoarthritis, the physiological constraints and limited intra-articular joint space prevent the use of large, solid drug delivery implants. Other investigators have explored the use of micro- and nanoparticle drug delivery systems. However, the small size of the systems limits the total drug that may be encapsulated and its short diffusion distance causes rapid release. Ordinarily, the extremely low diffusivity of a polymer fluid would make this an unsuitable delivery system. Our technology takes advantage of specific molecular interactions between drug and polymer, which can control the rate of release beyond diffusion. With this "affinity-based drug delivery", we have shown that delivery rates from solid polymer can be prolonged from hours and days, to weeks and months. In this paper, we demonstrate that this affinity-based mechanism also applies to low diffusivity fluid-phase polymers. They show release rates that are substantially slower than chemically similar polymers incapable of forming those inclusion complexes. The similarity of this study's liquid polymers to the viscoelastic fluids used in current clinical practice makes it an ample delivery system for osteoarthritic application. We confirmed the capacity of anti-inflammatory delivery of corticosteroids: hydrocortisone, triamcinolone, and dexamethasone; from both solid implants and polymer fluids. Further, we demonstrated that viscoelastic properties are widely tunable, and within the range of native synovial fluid. Lastly, we determined these polymer fluids have no impact on the differentiation of mesenchymal stem cells to cartilage and are not cytotoxic to a common cell line.

Impairment of chondrocyte proliferation after exposure of young murine cartilage to an aged systemic environment in a heterochronic parabiosis model

AIM:

The aim of this study was to investigate whether an aged systemic environment could impair young cartilage tissue in mice.

METHODS:

Mice differing in age were randomly divided into three groups. Group 1 was the experimental group (Y/O group) consisting of the heterochronic parabiosis model (2-month-old/12-month-old, young/old). Group 2 was the surgical control group (Y/Y group) with the isochronic parabiosis model (2-month-old/2-month-old, young/young). Group 3 consisted of the ageing control mice (2-month-old alone, Y group). Young knee cartilages collected from all three groups at 4 months after surgery were compared. Fluorescence molecular tomography (FMT) was used to confirm whether the two mice in parabiosis shared a common blood circulation at 2 weeks after surgery. The knee joints of young mice were examined radiologically at 4 months after surgery. Histological scoring was assigned to grade the severity of osteoarthritis (OA). Immunohistochemistry and quantitative reverse transcription polymerase chain reaction were used to evaluate OA-related protein expression and gene expression, and chondrocyte proliferation was determined with EdU staining.

RESULTS:

FMT imaging confirmed cross-circulation in the parabiotic pairs. The percentage of EdU-positive chondrocytes in young mice from the Y/O group was significantly lower compared with those of the Y/Y and Y groups (p <0.05 for both). There was no statistically significant difference in the mRNA expression of collagen type II (Col2), collagen type X (Col10), and matrix metalloproteinase 13 (MMP13) among the three groups (P>0.05), but expression of sex-determining region Y box 9 (Sox9) mRNA in young cartilage from the Y/O group was markedly attenuated compared to those in the Y/Y and Y groups (p <0.05 for both). In the Y/O group, mRNA expression of runt-related transcription factor 2 (Runx2) in young cartilage was significantly increased compared to the Y/Y and Y groups (p <0.05 for both). The changes in Col2, Col10, MMP13, Runx2 and Sox9 at the protein level mimicked the alterations found at the mRNA level. Loss of cartilage proteoglycan in young mice from the Y/O group was significantly greater compared to the Y/Y and Y groups (p <0.05 for both), despite the lack of significant difference among the three groups in OARIS and osteophytosis scores.

CONCLUSION:

Heterochronic parabiosis exerts a negative effect on chondrocyte proliferation in the knee cartilage of young mice.

Antiosteoarthritic Effects of ChondroT in a Rat Model of Monosodium Iodoacetate-Induced Osteoarthritis

Ganghwaljetongyeum is a traditional Korean herbal medicine used to treat joint pain, limited motion, fever, and swelling; it also inhibits inflammatory processes associated with arthritis. ChondroT, a water extract of Ganghwaljetongyeum, is a new complex herbal medicine. This study investigated the effects of ChondroT using a rat model of monosodium iodoacetate- (MIA-) induced osteoarthritis. Thirty-six rats were randomly divided into three ChondroT groups and a normal, control, and positive control group. Changes in paw edema volume, histopathology, and plantar withdrawal response were analyzed. Further, inflammatory cytokines, arachidonic acids, liver and kidney function, and hematological features were measured. ChondroT significantly decreased paw edema by the 5th day and notably improved articular cartilage damage; it also significantly improved the plantar withdrawal response in terms of both reaction time and force intensity. Moreover, treatment with ChondroT significantly decreased the serum levels of tumor necrosis factor alpha, interleukin-1β, interleukin-6, and prostaglandin E2 and significantly increased serum aspartate aminotransferase and alanine aminotransferase levels. This study demonstrates that ChondroT has anti-inflammatory and analgesic effects in a MIA-induced osteoarthritis rat model. These results support the clinical relevance of ChondroT for future use in patients with osteoarthritis. However, further studies are required to elucidate the corresponding mechanisms.

Extension of knee immobilization delays recovery of histological damages in the anterior cruciate ligament insertion and articular cartilage in rabbits

[Purpose] To investigate the influence of knee immobilization period on recovery of histological damages in the anterior cruciate ligament (ACL) insertion and articular cartilage in rabbits. This knowledge is important for determining the appropriate rehabilitation approach for patients with ligament injuries, fracture, disuse atrophy, and degenerative joint disease. [Materials and Methods] Forty-eight male Japanese white rabbits were divided equally into the remobilization and control groups. The remobilization group had the right knee surgically immobilized, and was divided equally into four subgroups according to the duration of immobilization (1, 2, 4 and 8 weeks). After the immobilization was removed, the rabbits moved freely for 8 weeks. The control group underwent sham operation and followed the same time course as the remobilization group. The chondrocyte apoptosis rate and chondrocyte proliferation rate in the ACL insertion and articular cartilage were analyzed after remobilization. [Results] In the ACL insertion, the remobilization group had a higher chondrocyte apoptosis rate than the control group after 8 weeks of immobilization, and a lower chondrocyte proliferation rate than the control group after 4 and 8 weeks of immobilization. In the articular cartilage, the remobilization group had a lower chondrocyte proliferation rate than the control group after 8 weeks of immobilization. After 8 weeks of remobilization, the ACL insertion and articular cartilage are not completely recovered after 4 and 8 weeks of immobilization, respectively. [Conclusion] Our results suggest that 8 weeks of remobilization will result in recovery of the ACL insertion after 2 weeks of knee immobilization, and recovery of the articular cartilage after 4 weeks of knee immobilization. If 8 weeks of immobilization occurs, a remobilization duration of more than 8 weeks may be necessary.

Hyaluronan in experimental injured/inflamed cartilage: In vivo studies

Joint disease is characterized by an imbalance between the synthesis and degradation of articular cartilage and subchondral bone accompanied by capsular fibrosis, osteophyte formation and varying degrees of inflammation of the synovial membrane. Many animal models have been developed to study arthritis and osteoarthritis that enable experimental conditions, diet and environmental risk factors to be carefully controlled. Animal-based studies have demonstrated the positive effects of exogenous HA on the preservation of joint cartilage in different models of arthritis and osteoarthritis. Although many promising effects of exogenous HA have been reported, there remains uncertainty as to its effectiveness in reversing cartilage injury and other manifestations of joint diseases because of difficulties in interpreting and unifying the results of these studies. A review of the literature of the last decade was conducted to report the results and to determine what we have learned from animal models in relation to joint inflammation induced by experimental models and HA treatment.

Effects of hyaluronic acid combined with anti-inflammatory drugs compared with hyaluronic acid alone, in clinical trials and experiments in osteoarthritis: a systematic review and meta-analysis

Background

The objectives are to compare the efficacy of intra-articular hyaluronic acid (IA-HA) alone and in combination with anti-inflammatory drugs (IA-HA + AI), corticosteroids (CS) or non-steroidal anti-inflammatory drugs (NSAIDs) in clinical trials and in vivo and in vitro studies of osteoarthritis (OA).

Methods

Data in the BIOSIS, CINAHL, Cochrane Library, EMBASE and Medline databases were collected and analyzed. Random effects models were used to compute the effect size (ES) of the mean difference in pain reduction scores from baseline and the relative risk (RR) of adverse events. The ES of histological scores in vivo and cartilage metabolism in vitro were also calculated. We conducted sensitivity analysis of blinding and intention-to-treat (ITT), compared IA-HA combined with CS vs. IA-HA alone in trials, and compared the effects of HA + AI vs. AI alone in vitro, including anabolic and catabolic gene expression.

Results

Thirteen out of 382 papers were included for data analysis. In clinical trials, the ES of pain reduction scores within the 1st month was −4.24 (−6.19, −2.29); 2nd–12th month, −1.39 (−1.95, −0.82); and within one year, −1.63 (−2.19, −1.08), favoring IA-HA + AI (P < 0.001). The ES of RR was 1.08 (0.59, 1.98), and histological scores was 1.38 (−0.55, 3.31). The ES of anabolic gene expression was 1.22 (0.18, 2.25), favoring HA alone (P < 0.05); catabolic gene expression was 0.74 (−0.44, 1.53), favoring HA alone; and glycosaminoglycans remaining was −2.45 (−5.94, 1.03).

Conclusions

IA-HA + AI had greater efficacy for pain relief than IA-HA alone within a one-year period. However, HA + AI down-regulated the ACAN gene when compared with HA alone in vitro.

Efficacy of Particulate Amniotic Membrane and Umbilical Cord Tissues in Attenuating Cartilage Destruction in an Osteoarthritis Model

Osteoarthritis (OA) is a progressive degenerative joint disease, and to date, no disease-modifying OA drug exists. Amniotic membrane and umbilical cord products have been used clinically in several diseases due to their anti-inflammatory and antiscarring properties. In the present study, we sought to evaluate whether a particulate amniotic membrane and umbilical cord (AM/UC) matrix could aid in attenuating disease progression. Lewis rats underwent medial meniscus transection (MMT) to induce OA. Two weeks after surgery, animals received intra-articular injections (50 μL) of either 50 or 100 μg/μL particulate AM/UC or saline control and were subsequently euthanized 1 or 4 weeks later. Cartilage degeneration was assessed using both histological scoring methods and equilibrium partitioning of an ionic contrast agent-microcomputed tomography (EPIC-μCT). EPIC-μCT analysis demonstrated that overall cartilage destruction was attenuated, with a significant increase in both cartilage thickness and volume as well as a significant decrease in total lesion area in animals injected with either dose of particulate AM/UC at 1 week, but only a high dose at 4 weeks postinjection. Osteoarthritis Research Society International (OARSI) histology scores of tibial sections corroborated EPIC-μCT results. Overall joint destruction was attenuated in animals injected with either dose of AM/UC tissue compared with saline-injected control animals at 1 week postinjection. Only high-dose AM/UC-injected animals continued to show less overall joint destruction by 4 weeks postinjection. Intra-articular injection of particulate AM/UC tissue attenuates cartilage degradation in a rat MMT model of OA, suggesting that it may be able to slow joint destruction in patients with OA.