Self-assembled hyaluronic acid nanoparticles for osteoarthritis treatment

Recent advances in extracellular matrix-inspired nanocarriers

INTRODUCTION

ECM-inspired nanocarriers have emerged as a promising platform for drug delivery due to their unique advantages over traditional nanocarrier systems. The ECM is a complex three-dimensional network comprising proteins and polysaccharides that play a key role in maintaining tissue function and homeostasis. Recent advances in the design and synthesis of ECM-inspired nanocarriers have resulted in superior efficacy, targeting, and responsive delivery systems.

AREAS COVERED

This review covers ECM-inspired nanocarriers, focusing on their design and fabrication methods, and applications in drug delivery, tissue engineering, and regenerative medicine. Specific focus is placed on nanocarriers derived from elastin, collagen, hyaluronic acid, and their combinations, creating 'conjugate nanoparticles' published in the last 5 years. This review also discusses the benefits of mimicking ECM structure and function, the advantages of each nanoparticle type, challenges associated with large-scale synthesis, and immunogenicity.

EXPERT OPINION

ECM-inspired nanocarriers are a novel avenue for the delivery of therapeutics with recent emphasis placed on complex, responsive systems. While substantial progress has been made in the design and application of these nanocarriers in pre-clinical studies, significant challenges remain, particularly concerning immunogenicity, scalability, and the need for more robust clinical data, before these innovations can be widely translated into clinical practice.

A multifunctional mitochondria-protective gene delivery platform promote intervertebral disc regeneration

Intervertebral disc degeneration (IDD) is a deleterious condition driven by localized inflammation and the associated disruption of the normal homeostatic balance between anabolism and catabolism, contributing to progressive functional abnormalities within the nucleus pulposus (NP). Despite our prior evidence demonstrating that a miR-21 inhibitor can have regenerative effects that counteract the progression of IDD, its application for IDD treatment remains limited by the inadequacy of current local delivery systems. Here, an injectable tannic acid (TA)-loaded hydrogel gene delivery system was developed and used for the encapsulation of a multifunctional mitochondria-protecting gene nanocarrier (PHs). This engineered platform was designed for the sustained on-demand delivery of both miR-21 inhibitor and ss-31 (mitochondrial-targeted peptide) constructs to the NP. This prepared hydrogel could be implanted into the intervertebral disc using a minimally invasive approach whereupon it was able to rapidly release TA. Sustained PHs release was then achieved as appropriate through a mechanism mediated by the activity of MMP-2. Following the targeted uptake of PHs by degenerated NP cells, the subsequent release of encapsulated miR-21 inhibitor suppressed apoptotic cell death and modulated the metabolism of the extracellular matrix (ECM) by targeting the Spry1 gene. At the same time, ss-31 was able to target damaged mitochondria and alleviate inflammatory activity via the suppression of mitochondrial ROS-NLRP3-IL-1β/Caspase1 pathway activity. Synergistic ECM regeneration and anti-inflammatory effects were sufficient to provide therapeutic benefits in an in vivo model of IDD. Together, these results thus highlight this hydrogel-based gene delivery platform as a promising novel approach to the treatment of IDD.

Drug-free hyaluronic acid-microneedle with unexpected inhibition activity on benzalkonium chloride-induced corneal inflammation and stromal scarring

Topical instilling of commercial artificial tears (cAT, containing 0.1 % hyaluronic acid) is widely employed to alleviate clinical manifestations of mild dry eye disease (DED) by preventing the pathological change of corneal epithelium. However, it showed limited therapy effectiveness on heavy DED which has further involved corneal stroma, due to its low stroma-available for hyaluronic acid (HA) resulting from the barrier of corneal epithelium. The present study developed a new microneedle-dosage form of cAT (cAT-MN). This cAT-MN can overstride the corneal epithelium and act as a long-lasting protective agent. Compared to cAT dosing (4 times/day), cAT-MN with one treatment exerted significantly higher therapeutic effects on curbing benzalkonium chloride (BAC)-induced corneal stroma scaring as well as alleviating the DED symptoms in the first 5-day BAC exposure; whereas, showed limited effects in a 10-day BAC exposure. To expand the therapy effects, MNs containing various amounts of HA were prepared. Thereinto, HA(6 %)-MN recovered corneal damage to healthy levels, which could be attributed to adding stroma-available for HA both by increasing the amounts of HA-delivery and enhancing HA-permeation. This study explores a new drug-free microneedle-dosage form of cAT to cure corneal stroma disorders which has expanded its indication, promising a wide clinical use in ophthalmology.

Theranostics of osteoarthritis: Applications and prospects of precision targeting nanotechnology

Osteoarthritis (OA), a complex degenerative joint disease driven by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, lacks effective disease-modifying therapies. Precision-targeted nanotechnology has emerged as a breakthrough strategy, offering enhanced drug delivery, reduced toxicity, and synergistic diagnostic-therapeutic capabilities. This review summarizes OA pathogenesis, focusing on dysregulated immune networks and self-perpetuating synovial microenvironmental interactions. We discuss advanced nanomedicine approaches, which leverage OA-specific pathological cues for localized treatment. Innovations in cytokine modulation, photothermal therapy, and integrated theranostics (photoacoustic/fluorescence imaging) are highlighted as transformative tools for real-time diagnosis and personalized intervention. Despite progress, challenges such as biocompatibility optimization, clinical translation barriers, OA heterogeneity necessitate further development of multifunctional nanocarriers and rationaldesigns. This work underscores the potential of nanotechnology to advance OA therapeutics, bridging preclinical innovation with clinical applicability in pharmaceutical sciences.

Size-controlled immunomodulatory and vaccine adjuvant potentials of self-assembled hyaluronic acid nanoparticles: Activation and recruitment of immune cells

Immunotherapy has paramount importance in treating chronic immune diseases, and vaccine development. Hyaluronic acid (HA) has been shown to elicit molecular weight-related distinct immune responses. Nonetheless, the particle size-dependent immunomodulatory effects of hyaluronic acid nanoparticles (HA-NPs) remain blurred. Thus, the present study aimed at investigating the effect of polymer configuration and particle size of HA-NPs assembled from HA36K-ODA and HA360k-ODA analogs in modulating macrophage-related immune activities. In the in vitro experiments, HA-NPs of HA36k-ODA analogs garnered significantly enhanced nitrite production with low interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) secretion in macrophages. Furthermore, smaller (< 200 nm) HA36k-ODA NPs activated CD11b+ cells whereas a ∼ 130 nm HA36k-ODA15 NPs preferentially induced CD11c+ cells in vivo, indicating the influence of particle size on the antigen-presenting cells (APCs) recruitment. Interestingly, self-assembled HA36k-ODA15 NPs without ovalbumin (OVA) activated immature dendritic cells (DCs) and augmented their migration toward the lymph nodes (LNs). Notably, HA36k-ODA15-activated macrophages behaved like M1 phenotype macrophages. Overall, our findings garnered valuable insights about the design and application of HA-NPs for modulating the immune responses in nanoscale materials-based immunotherapy.

Hyaluronic acid composite hydrogel with enhanced lubrication and controllable drug release for the mitigation of osteoarthritis

Excessive inflammation, overexpressed reactive oxygen species (ROS), degradation of the extracellular matrix, and high friction aggravate osteoarthritis (OA). Intra-articular injection for local drug delivery in the joint cavity enhances drug retention duration for OA treatment. Nevertheless, it remains a challenge to attenuate OA by thoroughly modulating the joint microenvironment, achieving controlled drug release, and enhancing lubrication. This study develops hyaluronic acid (HA) composite hydrogels, infused with gelatin microspheres containing a drug, utilizing dynamic interactions between phenylboronic acid and catechol to modulate the microenvironment by scavenging ROS, facilitating controlled drug release, and improving lubrication to mitigate OA. The composite hydrogels can be injected by intra-articular injection due to the shear-thinning properties, demonstrating broad ROS scavenging capacity and matrix metalloproteinase-9 responsive drug release. Both the in vitro and in vivo experiments prove the protective efficacy of the composite hydrogels against the degradation of cartilage matrix. Additionally, the hydrogels can offer efficient lubrication and effectively attenuate OA. Thus, the injectable HA composite hydrogels demonstrated potential in the management of OA.

Hyaluronic acid/ε-polylysine hydrogel enriched with Saussurea involucrata polysaccharide for improved skin dryness induced by ultraviolet radiation

Ultraviolet B (UVB) radiation exposure is a major contributor to skin photoaging, ultimately resulting in dryness. Conventional treatments for this condition frequently exhibit limited efficacy due to poor skin penetration and are associated with significant side effects. Saussurea involucrate polysaccharide (SIP) has been shown to alleviate photoaging-induced dry skin; however, its effectiveness is limited due to low drug utilization and the need for frequent dosing. In this study, we developed hyaluronic acid (HA) and ε-polylysine (ε-PLL) hydrogels designed to enhance skin hydration and enable sustained drug release. The optimal formulation, designated A5E3, contained 5 % HA plus 3 % ε-PLL. The sustained release of SIP from A5E3 demonstrated superior therapeutic effects in a mouse model of skin photoaging, including reduced inflammation and apoptosis, as well as enhanced keratinocyte differentiation and lipid production. The A5E3 hydrogel not only enhanced the drug utilization of SIP but also provided a sustained moisturizing environment, promoting faster skin repair. These findings support the development of skincare products with superior moisturizing and reparative properties, underscoring the potential of hydrogels as effective carriers for treating UVB-induced skin dryness and damage.

Design Strategies for Hyaluronic Acid-based Drug Delivery Systems in Cancer Immunotherapy

Despite its robust therapeutic potential, cancer immunotherapy has provided little progress towards improved survival rates for patients bearing immunologically refractory tumors. The implementation of advanced drug delivery systems represents a powerful means of improving cancer immunotherapy by relieving immunosuppression and promoting immune response; however, the overall impact of these systems on immunotherapy currently remains modest. Hyaluronic acid represents a widely used polymer in drug delivery; meanwhile, recent studies linking hyaluronic acid to the immune system make this polymer an attractive component in the design of next-generation cancer immunotherapies. Herein, we review our current understanding of the immunological properties of hyaluronic acid and discuss them in the context of bioactive functions and immune-related interactions with receptors, immune, and cancer cells. We analyze the potential of hyaluronic acid as a component in advanced drug delivery systems, highlighting strategies for the design of more effective vaccines and cancer chemo-immunotherapies. Finally, we discuss critical considerations to facilitate design and clinical translation to overcome existing challenges and maximize therapeutic potential.

Comprehensive multi-omics approach reveals potential therapeutic targets and agents for osteoarthritis

BACKGROUND

The mechanisms underlying osteoarthritis (OA) remain unclear, and effective treatments are lacking. This study aims to identify OA-related genes and explore their potential in drug repositioning for OA treatment.

METHODS

Transcriptome-wide association studies (TWAS) were performed using genome-wide association studies summary data and expression quantitative trait loci data from the Genotype-Tissue Expression project. Differentially expressed genes between OA patients and healthy controls were identified using four datasets from the Gene Expression Omnibus database. Gene ontology and pathway enrichment analyses identified potential hub genes associated with OA. A network-based drug repositioning approach was applied to discover potential therapeutic drugs for OA.

RESULTS

Through TWAS and mRNA expression profiling, 7 and 167 OA-related genes were identified, respectively. From these, 128 OA-related genes were selected based on common biological processes. Using the maximal clique centrality algorithm, 10 core-related genes (JUN, VEGFA, FN1, CD44, PTGS2, STAT1, MAP 2K7, GRB2, EP300, and PXN) were identified for network-based drug repositioning. Consequently, 24 drugs were identified based on 128 OA-related genes and 23 drugs based on 10 core OA-related genes. Some identified drugs, such as dexamethasone, menadione, and hyaluronic acid, have been previously reported for OA and/or rheumatoid arthritis treatment. Network analysis also indicated that spironolactone, lovastatin, and atorvastatin may have potential in OA treatment.

CONCLUSION

This study identified potential OA-related genes and explored their roles in drug repositioning, suggesting the repurposing of existing drugs and the development of new therapeutic options for OA patients. Key message What is already known on this topic The exact pathogenesis of osteoarthritis (OA) remains unclear, and currently, there are no approved drugs that can prevent, halt, or inhibit the progression of OA. What this study adds We identified 128 OA-related genes and 10 core-related genes based on common biological processes revealed by TWAS and mRNA expression profiling. Using these genes, we discovered potential drugs for OA through the Network-based drug repositioning method. How this study might affect research, practice, or policy This study provides recommendations for repositioning existing drugs and developing new treatment options for patients with OA.

Carbohydrate-based polymer nanocarriers for environmentally friendly applications

Effective delivery of active substances and drugs is an important part of treatment. In order for a drug to work at the right place in the body, it must be transported there in the right way. For this reason, new carriers are being sought for active substances and drugs that can effectively deliver drugs to the target site without causing additional side effects. These include nanoparticles, microneedles, cubosomes and nanogels, among others. Recently, carriers based on biodegradable polymers such as hyaluronic acid or chitosan are becoming popular. In addition, modern carriers are designed to release the active ingredient in response to a specific agent. This paper reviews the literature from the past 5 years on novel delivery systems with medical, agricultural, food and cosmetic applications, with a special emphasis on the use of carbohydrate-based nanocarriers.

Sodium alginate microspheres loaded with Quercetin/Mg nanoparticles as novel drug delivery systems for osteoarthritis therapy

BACKGROUND

Osteoarthritis (OA) is the most prevalent arthritic disease characterized by cartilage degradation and low-grade inflammation, for which there remains a lack of efficacious therapeutic interventions. Notably, mitigating the impact of oxidative stress (OS) and inflammatory factors could help alleviate or hinder the advancement of OA. Given the benefits of both quercetin (Que) and Magnesium ion (Mg2+) in OA treatment, coupled with the structural properties of Que, we have innovatively developed the Que-Mg2+ nanoparticles (NPs), aiming to deliver both Que and Mg2+ simultaneously and achieve enhanced therapeutic outcomes for OA. Moreover, to avoid the adverse reactions linked to frequent injections, sodium alginate (SA) microspheres encapsulating Que-Mg2+ NPs (Que-Mg@SA) were designed to treat the H2O2-induced OA cell model.

METHODS

Que-Mg@SA microspheres were synthesized using the ionotropic gelation technique, with calcium chloride acting as the cross-linking agent. Comprehensive characterization of the Que-Mg@SA was conducted through transmission electron microscope (TEM), dynamic light scattering (DLS), optical microscope, and scanning electron microscope (SEM), which provided detailed insights into their size, zeta potential, morphology, and micromorphology. Additionally, the microsphere swelling rate and Que release were evaluated. The biocompatibility of Que-Mg@SA microspheres, along with their impact on chondrocyte viability, were detected through CCK-8 assay and live/dead cell staining. Furthermore, the antioxidant and anti-inflammatory properties of Que-Mg@SA were evaluated by examining the ROS scavenging ability and pro-inflammatory factors levels, respectively. Finally, the regulatory influence of Que-Mg@SA microspheres on extracellular matrix (ECM) metabolism in OA was assessed by immunofluorescence staining and Western blot.

RESULTS

Characterization results revealed that Que-Mg NPs exhibit nanoscale diameter, exceptional stability, and good dispersibility, while Que-Mg@SA possesses high entrapment efficiency (EE%) and loading efficiency (LE%), pronounced hygroscopic properties, and sustained drug-release capabilities. Additionally, in vitro cellular assays revealed that the biocompatible Que-Mg@SA microspheres significantly restored chondrocyte viability, scavenged H2O2-induced excessive ROS, reduced the levels of inflammatory cytokines, upregulated cartilage anabolic gene expression, downregulated cartilage catabolic protease gene expression, and maintained the metabolic balance of cartilage tissue.

CONCLUSION

The functionalized Que-Mg@SA microspheres developed in our study hold great promise as a drug delivery system for OA and potentially other biomedical applications.

CLINICAL TRIAL NUMBER

Not applicable.

Lubrication for Osteoarthritis: From Single-Function to Multifunctional Lubricants

Osteoarthritis (OA) is a common degenerative joint disease that progressively destroys articular cartilage, leading to increased joint friction and severe pain. Therefore, OA can be treated by restoring the lubricating properties of cartilage. In this study, recent advances in lubricants for the treatment of OA are reviewed for both single-function and multifunctional lubricants. Single-function lubricants mainly include glycosaminoglycans, lubricin, and phospholipids, whereas multifunctional lubricants are composed of lubricating and anti-inflammatory bifunctional hydrogels, stem cell-loaded lubricating hydrogels, and drug-loaded lubricating nanoparticles. This review emphasizes the importance of restoring joint lubrication capacity for the treatment of OA and explores the structural features, lubrication properties, and role of these lubricants in modulating intracellular inflammatory responses and metabolism. Current challenges and future research directions in this field are also discussed, with the aim of providing a scientific basis and new ideas for the clinical treatment of OA.

Remodeling the Proinflammatory Microenvironment in Osteoarthritis through Interleukin-1 Beta Tailored Exosome Cargo for Inflammatory Regulation and Cartilage Regeneration

Osteoarthritis (OA) presents a significant therapeutic challenge, with few options for preserving joint cartilage and repairing associated tissue damage. Inflammation is a pivotal factor in OA-induced cartilage deterioration and synovial inflammation. Recently, exosomes derived from human umbilical cord mesenchymal stem cells (HucMSCs) have gained recognition as a promising noncellular therapeutic modality, but their use is hindered by the challenge of harvesting a sufficient number of exosomes with effective therapeutic efficacy. Given that HucMSCs are highly sensitive to microenvironmental signals, we hypothesized that priming HucMSCs within a proinflammatory environment would increase the number of exosomes secreted with enhanced anti-inflammatory properties. Subsequent miRNA profiling and pathway analysis confirmed that interleukin-1 beta (IL-1β)-induced exosomes (C-Exos) exert positive effects through miRNA regulation and signaling pathway modulation. In vitro experiments revealed that C-Exos enhance chondrocyte functionality and cartilage matrix production, as well as macrophage polarization, thereby enhancing cartilage repair. C-Exos were encapsulated in hyaluronic acid hydrogel microspheres (HMs) to ensure sustained release, leading to substantial improvements in the inflammatory microenvironment and cartilage regeneration in a rat OA model. This study outlines a strategy to tailor exosome cargo for anti-inflammatory and cartilage regenerative purposes, with the functionalized HMs demonstrating potential for OA treatment.

Reactive oxygen species-sensitive fenofibrate-loaded dextran nanoparticles in alleviation of osteoarthritis

Osteoarthritis (OA) stands as a prevalent chronic joint pathology, emerging as a leading cause of disability on a global scale. However, the current therapeutic efficacy in OA treatment remains unsatisfactory. Chondrocyte ferroptosis has become to a critical target for OA treatment, while the fabrication of nanomedicines emerges as a promising strategy for OA treatment. Nevertheless, there exists a paucity of reported nanomedicine systems designed to combat chondrocyte ferroptosis for OA alleviation. In light of this, our study introduced a reactive oxygen species (ROS)-sensitive fenofibrate-loaded targeted nanoparticle (FN-CNPs) as a means of alleviating OA by suppressing chondrocyte ferroptosis. In vitro investigations demonstrated the FN-CNPs can achieve this through the reduction of lipid peroxidation and ROS levels, as well as the elevation of anti-ferroptosis markers (GPX4, FSP1, and ACSL3). Consequently, FN-CNPs exhibited significant anti-inflammatory effects and downregulated the expression of key catabolic mediators in vitro. Furthermore, in vivo studies underscored the ability of FN-CNPs to alleviate OA progression and protect cartilage. Collectively, these findings highlight the efficacy of FN-CNPs in mitigating OA progression by suppressing chondrocyte ferroptosis via regulating ROS levels, antioxidant systems and lipid metabolism of chondrocytes.

Hyaluronan Tetrasaccharides Penetrate into the Skin by Passive Diffusion and Contribute to Skin Health

Hyaluronan (HA) is a commonly used material in cosmetics and pharmaceuticals because of its various pharmacological activities. However, because of its large molecular weight, HA penetrates the skin very poorly and most of it remains on the skin surface. Thus, topically applied HA could not be expected to function biologically in the skin. However, we have confirmed that HA tetrasaccharides (HA4), which is the smallest unit of HA, penetrate into the skin by passive diffusion and affect epidermal metabolism. Topical treatment of HA4 rescues the epidermal damage caused by long-term UVA irradiation. Furthermore, various biological functions of HA4 to maintain healthy skin was observed in cell culture studies. This review describes the skin permeability of HA4 and how it contributes to healthy skin.

An intra articular injectable Mitocelle recovers dysfunctional mitochondria in cellular organelle disorders

Mitochondrial dysfunction increases ROS production and is closely related to many degenerative cellular organelle diseases. The NOX4-p22phox axis is a major contributor to ROS production and its dysregulation is expected to disrupt mitochondrial function. However, the field lacks a competitive inhibitor of the NOX4-p22phox interaction. Here, we created a povidone micelle-based Prussian blue nanozyme that we named "Mitocelle" to target the NOX4-p22phox axis, and characterized its impact on the major degenerative cellular organelle disease, osteoarthritis (OA). Mitocelle is composed of FDA-approved and biocompatible materials, has a regular spherical shape, and is approximately 88 nm in diameter. Mitocelle competitively inhibits the NOX4-p22phox interaction, and its uptake by chondrocytes can protect against mitochondrial malfunction. Upon intra-articular injection to an OA mouse model, Mitocelle shows long-term stability, effective uptake into the cartilage matrix, and the ability to attenuate joint degradation. Collectively, our findings suggest that Mitocelle, which functions as a competitive inhibitor of NOX4-p22phox, may be suitable for translational research as a therapeutic for OA and cellular organelle diseases related to dysfunctional mitochondria.

Enhanced therapeutic potential of a self-healing hyaluronic acid hydrogel for early intervention in osteoarthritis

Osteoarthritis (OA) is characterized by symptoms such as abnormal lubrication function of synovial fluid and heightened friction on the cartilage surface in its early stages, prior to evident cartilage damage. Current early intervention strategies employing lubricated hydrogels to shield cartilage from friction often overlook the significance of hydrogel-cartilage adhesion and enhancement of the cartilage extracellular matrix (ECM). Herein, we constructed a hydrogel based on dihydrazide-modified hyaluronic acid (HA) (AHA) and catechol-conjugated aldehyde-modified HA (CHA), which not only adheres to the cartilage surface as an effective lubricant but also improves the extracellular environment of chondrocytes in OA. Material characterization experiments on AHA/CHA hydrogels with varying concentrations validated their exceptional self-healing capabilities, superior injectability and viscoelasticity, sustained adhesion strength to cartilage, and a low friction coefficient. Chondrocytes exhibited robust adhesion and proliferation on the AHA/CHA hydrogel surface, with the upregulation of cartilage matrix protein expression. Intra-articular injection of AHA/CHA hydrogels was performed following destabilization of the medial meniscus (DMM) surgery in mice to assess its protective effect on cartilage. The AHA/CHA hydrogel effectively attenuated the degree of cartilage wear, facilitated chondrocytes' anabolic metabolism, and restored the ECM of cartilage. Therefore, the AHA/CHA hydrogel emerges as a promising therapeutic approach in clinical practices of OA treatment.

Recent Strategies and Advances in Hydrogel-Based Delivery Platforms for Bone Regeneration

Bioactive molecules have shown great promise for effectively regulating various bone formation processes, rendering them attractive therapeutics for bone regeneration. However, the widespread application of bioactive molecules is limited by their low accumulation and short half-lives in vivo. Hydrogels have emerged as ideal carriers to address these challenges, offering the potential to prolong retention times at lesion sites, extend half-lives in vivo and mitigate side effects, avoid burst release, and promote adsorption under physiological conditions. This review systematically summarizes the recent advances in the development of bioactive molecule-loaded hydrogels for bone regeneration, encompassing applications in cranial defect repair, femoral defect repair, periodontal bone regeneration, and bone regeneration with underlying diseases. Additionally, this review discusses the current strategies aimed at improving the release profiles of bioactive molecules through stimuli-responsive delivery, carrier-assisted delivery, and sequential delivery. Finally, this review elucidates the existing challenges and future directions of hydrogel encapsulated bioactive molecules in the field of bone regeneration.

The Role of Nanoparticles in Accelerating Tissue Recovery and Inflammation Control in Physiotherapy Practices

Physiotherapy has significantly evolved since its inception in the late 19th century, expanding into various specializations such as sports, neurology, and wound care. Its primary goal is to restore or enhance bodily functions through therapeutic interventions, aiding in conditions ranging from injuries to chronic pain. Tissue recovery, which involves repair and regeneration, is a critical aspect of physiotherapy. This natural process is influenced by factors like inflammation and injury severity. Nanotechnology, a relatively recent advancement, has transformed medicine, including wound care, through innovations in drug delivery, diagnostics, and anti-inflammatory treatments. Nanoparticles, owing to their small size and enhanced bioavailability, play a crucial role in improving drug delivery, increasing the efficacy of treatments, and promoting faster recovery. In the context of tissue healing, nanoparticles aid in cell proliferation, inflammation control, and scar reduction, among other therapeutic benefits. They are increasingly used in physiotherapy applications, to support tissue regeneration and inflammation management. This review examines the role of nanoparticles in physiotherapy, with a focus on their application in wound healing, muscle recovery, and inflammation control. It discusses various in-vitro and in-vivo studies that have explored the therapeutic potential of nanoparticles in these domains, providing insights into their mechanisms of action and effectiveness in promoting tissue regeneration and managing inflammation in physiotherapy settings.

Inspired by lubricin: a tailored cartilage-armor with durable lubricity and autophagy-activated antioxidation for targeted therapy of osteoarthritis

Osteoarthritis (OA), which disables articular cartilage, affects millions of people. The self-healing capacity is inhibited by internal oxidative stress and external lubrication deficiency and enzymatic degradation. To overcome these challenges, a tailored cartilage-armor is designed to ameliorate the inflamed cartilage, which is implemented by a novel collagen type II (Col II)-binding peptide conjugated zwitterionic polymer (PSB-b-PColBP, PSP). By mimicking natural lubricin, PSP specifically targets the cartilage surface and forms an in situ hydration armor. This engineered cartilage-armor can prevent enzymatic cartilage degradation (nearly 100% resistance to catabolic enzymes) and provide durable lubrication properties (COF < 0.013 for 500 cycles). An autophagy-activation process, absent in previous biomimetic lubricants, enhances the enzymatic activity of the tailored cartilage-armor, offering effective anti-oxidant properties to suppress oxidative stress. By inhibiting the PI3K-Akt/NF-κB signaling pathway, chondrocytes protected by the tailored armor can secrete a cartilage matrix even in inflammatory microenvironments. In OA rat models, osteophyte formation and the inflammatory response have been inhibited by the cartilage-armor, demonstrating a therapeutic effect comparable to most drug-loaded systems. This study underscores the potential of tailoring cartilage-armor with the cartilage targeting and autophagy-activating properties in integrating offensive-defensive mechanisms for cartilage remodeling. This represents an alternative strategy for clinical OA therapy.

Enzyme-responsive microgel with controlled drug release, lubrication and adhesion capability for osteoarthritis attenuation

The treatment of osteoarthritis (OA) remains challenging due to the narrow therapeutic window and rapid clearance of therapeutic agents, even with intra-articular administration, resulting in a low treatment index. Recent advancements in local drug delivery systems have yet to overcome the issues of uncontrolled burst release and short retention time, leading to suboptimal OA treatment outcome. Herein, we developed a methacrylate-crosslinking hyaluronic acid (HA) microgel (abbreviated as CXB-HA-CBP) that covalently conjugates the anti-inflammatory drug celecoxib (CXB) via a metalloproteinase-2 (MMP-2)-responsive peptide linker (GGPLGLAGGC) and a collagen II binding peptide (WYRGRLC). The GGPLGLAGGC linker is specifically cleaved by the overexpressed MMP-2 enzyme within the OA joint, enabling the sustained and on-demand release of CXB entity. The synergistic action of CXB and HA effectively inhibited macrophage activation and reduced the production of pro-inflammatory cytokines, protecting chondrocytes from damage. Furthermore, the collagen II peptide introduced on the microgel surface enabled a cartilage-binding function to form an artificial lubrication microgel layer on the cartilage surface to reduce cartilage wear. The CXB-HA-CBP microgel showed an extended retention time of up to 18 days in the affected joint, leading to an effective OA treatment in rats. This sophistically designed microgel, characterized by the prolonged retention time, sustained drug delivery, and enhanced lubrication, presents a promising biomedicine for OA treatment. STATEMENT OF SIGNIFICANCE: A new methacrylate-crosslinking hyaluronic acid (HA) microgel, covalently conjugated with the celecoxib (CXB)-GGPLGLAGGC and the collagen II binding peptide (CBP, peptide sequence: WYRGRLC), was developed. The overexpressed MMP-2 in OA joint cleaved the GGPLGLAGGC linker to trigger the CXB moiety release. Besides, the CBP on the surface of microgels enabled a cartilage-attaching ability, resulting in a prolonged retention time and an improved lubrication property in joint. This advanced drug-loading microgel remarkably reduced macrophage activation and pro-inflammation cytokine production, while protecting the chondrocytes via a dual action of CXB and HA. This study demonstrated that the enzyme-responsive drug-loading microgel could serve as an platform to efficiently attenuate osteoarthritis.

Rosmarinic acid promotes cartilage regeneration through Sox9 induction via NF-κB pathway inhibition in mouse osteoarthritis progression

Background

The natural polyphenolic compound known as Rosmarinic acid (RosA) can be found in various plants. Although its potential health benefits have been extensively studied, its effect on osteoarthritis (OA) progression and cartilage regeneration function still needs to be fully elucidated in OA animal models. This study elucidated the effect of RosA on OA progression and cartilage regeneration.

Methods

In vitro assessments were conducted using RT-PCR, qRT-PCR, Western blotting, and ELISA to measure the effects of RosA. The molecular mechanisms of RosA were determined by analyzing the translocation of p65 into the nucleus using immunocytochemistry (ICC). Histological analysis of cartilage explant was performed using alcian blue staining and immunohistochemistry (IHC). For in vivo analysis, the destabilization of the medial meniscus (DMM)-induced OA mouse model was utilized to evaluate cartilage destruction through Safranin-O staining. The expression of catabolic and anabolic factors in mice knee joints was quantified by immunohistochemistry.

Results

The expression of catabolic factors in chondrocytes was significantly impeded by RosA. It also suppressed the NF-κB signaling pathway by decreasing phosphorylation of p65 and reducing degradation of IκB protein. In ex vivo experiments, RosA protected sulfated proteoglycan erosion triggered by IL-1β and suppressed the catabolic factors in cartilage explant. RosA treatment in animal models resulted in preventing cartilage destruction and reducing catabolic factors in the cartilage. RosA was also found to promote the expression of Sox9, Col2a1, and Acan in vitro, ex vivo, and in vivo analyses.

Conclusions

RosA attenuated the OA progression by suppressing the catabolic factors expression. These effects were facilitated through the suppression of the NF-κB signaling pathway. Additionally, it promotes cartilage regeneration by inducing anabolic factors. Therefore, RosA shows potential as an effective therapeutic agent for treating OA.

Application of adhesives in the treatment of cartilage repair

From degeneration causing intervertebral disc issues to trauma‐induced meniscus tears, diverse factors can injure the different types of cartilage. This review highlights adhesives as a promising and rapidly implemented repair strategy. Compared to traditional techniques such as sutures and wires, adhesives offer several advantages. Importantly, they seamlessly connect with the injured tissue, deliver bioactive substances directly to the repair site, and potentially alleviate secondary problems like inflammation or degeneration. This review delves into the cutting‐edge advancements in adhesive technology, specifically focusing on their effectiveness in cartilage injury treatment and their underlying mechanisms. We begin by exploring the material characteristics of adhesives used in cartilage tissue, focusing on essential aspects like adhesion, biocompatibility, and degradability. Subsequently, we investigate the various types of adhesives currently employed in this context. Our discussion then moves to the unique role adhesives play in addressing different cartilage injuries. Finally, we acknowledge the challenges currently faced by this promising technology.

Development of a dexamethasone-hyaluronic acid conjugate with selective targeting effect for acute lung injury therapy

Acute lung injury (ALI), a critical complication of COVID-19, is characterized by widespread inflammation and severe pulmonary damage, necessitating intensive care for those affected. Although glucocorticoids (GCs), such as dexamethasone (Dex), have been employed clinically to lower mortality, their nonspecific systemic distribution has led to significant side effects, limiting their use in ALI treatment. In this study, we explored the conjugation of Dex to hyaluronic acid (HA) to achieve targeted delivery to inflamed lung tissues. We achieved a conjugation efficiency exceeding 98 % using a cosolvent system, with subsequent ester bond cleavage releasing the active Dex, as verified by liquid chromatography. Biodistribution and cellular uptake studies indicated the potential of the HA conjugate for cluster of differentiation 44 (CD44)-mediated targeting and accumulation. In a lipopolysaccharide-induced ALI mouse model, intravenous (IV) HA-Dex administration showed superior anti-inflammatory effects compared to free Dex administration. Flow cytometry analysis suggested that the HA conjugate preferentially accumulated in lung macrophages, suggesting the possibility of reducing clinical Dex dosages through this targeted delivery approach.

Biomaterials Mimicking Mechanobiology: A Specific Design for a Specific Biological Application

Mechanosensing and mechanotransduction pathways between the Extracellular Matrix (ECM) and cells form the essential crosstalk that regulates cell homeostasis, tissue development, morphology, maintenance, and function. Understanding these mechanisms involves creating an appropriate cell support that elicits signals to guide cellular functions. In this context, polymers can serve as ideal molecules for producing biomaterials designed to mimic the characteristics of the ECM, thereby triggering responsive mechanisms that closely resemble those induced by a natural physiological system. The generated specific stimuli depend on the different natural or synthetic origins of the polymers, the chemical composition, the assembly structure, and the physical and surface properties of biomaterials. This review discusses the most widely used polymers and their customization to develop biomaterials with tailored properties. It examines how the characteristics of biomaterials-based polymers can be harnessed to replicate the functions of biological cells, making them suitable for biomedical and biotechnological applications.

Targeting inflammation with hyaluronic acid-based micro- and nanotechnology: A disease-oriented review

Inflammation is a pivotal immune response in numerous diseases and presents therapeutic challenges. Traditional anti-inflammatory drugs and emerging cytokine inhibitors encounter obstacles such as limited bioavailability, poor tissue distribution, and adverse effects. Hyaluronic acid (HA), a versatile biopolymer, is widely employed to deliver therapeutic agents, including anti-inflammatory drugs, genes, and cell therapies owing to its unique properties, such as hydrophilicity, biodegradability, and safety. HA interacts with cell receptors to initiate processes such as angiogenesis, cell proliferation, and immune regulation. HA-based drug delivery systems offer dual strategies for effective inflammation management, capitalizing on passive and active mechanisms. This synergy permits the mitigation of inflammation by lowering the doses of anti-inflammatory drugs and their off-target adverse effects. A diverse array of micro- and nanotechnology techniques enable the fabrication of tailored HA-engineered systems, including hydrogels, microgels, nanogels, microneedles, nanofibers, and 3D-printed scaffolds, for diverse formulations and administration routes. This review explores recent insights into HA pharmacology in inflammatory conditions, material design, and fabrication methods, as well as its applications across a spectrum of inflammatory diseases, such as atherosclerosis, psoriasis, dermatitis, wound healing, rheumatoid arthritis, osteoarthritis, inflammatory bowel disease, and colitis, highlighting its potential for clinical translation.

Advances in hyaluronic acid: Bioactivity, complexed biomaterials and biological application: A review

Hyaluronic acid (HA) is a natural glycosaminoglycan found in the human body, particularly in the extracellular matrix of body fluids and tissues. It plays a critical role in cellular processes of living organisms by maintaining tissue hydration, cell proliferation, differentiation, and inflammatory response. HA exhibits significant biological activity in skin care, aesthetic anti-aging, medical orthopedic repair, gynecological cancer monitoring, and other pathological conditions. Due to its exceptional biocompatibility, biodegradability, lack of toxicity, non-immunogenicity, and its capacity to bond with other substances, various HA-based biomedical products like hydrogels, microneedles, and microspheres have been developed. These innovations have also been applied in various medical and health fields, such as bone and tissue regeneration, gels for medical aesthetic fillers, and gynecology-related cancer treatment, utilizing the HA drug delivery pathway. The interest in HA and its products is increasing due to their biological functions. Therefore, this review aimed to summarize the biological properties of HA and to focus on its applications in the bone tissue engineering and healthcare, for HA has some practical applications of HA-based complexes in biomedical materials, tissue repair, medical aesthetics, and gynecology. Through this review, we seek to offer theoretical research assistance for the development of HA-based bioproducts in the healthcare domain and provide innovative insights for human health.

Stem cell recruitment polypeptide hydrogel microcarriers with exosome delivery for osteoarthritis treatment

With the accelerated aging tendency, osteoarthritis (OA) has become an intractable global public health challenge. Stem cells and their derivative exosome (Exo) have shown great potential in OA treatment. Research in this area tends to develop functional microcarriers for stem cell and Exo delivery to improve the therapeutic effect. Herein, we develop a novel system of Exo-encapsulated stem cell-recruitment hydrogel microcarriers from liquid nitrogen-assisted microfluidic electrospray for OA treatment. Benefited from the advanced droplet generation capability of microfluidics and mild cryogelation procedure, the resultant particles show uniform size dispersion and excellent biocompatibility. Moreover, acryloylated stem cell recruitment peptides SKPPGTSS are directly crosslinked within the particles by ultraviolet irradiation, thus simplifying the peptide coupling process and preventing its premature release. The SKPPGTSS-modified particles can recruit endogenous stem cells to promote cartilage repair and the released Exo from the particles further enhances the cartilage repair performance through synergistic effects. These features suggest that the proposed hydrogel microcarrier delivery system is a promising candidate for OA treatment.

FGF18 encoding circular mRNA-LNP based on glycerolipid engineering of mesenchymal stem cells for efficient amelioration of osteoarthritis

Mesenchymal stem cells (MSCs) exhibit substantial potential for osteoarthritis (OA) therapy through cartilage regeneration, yet the realization of optimal therapeutic outcomes is hampered by their limited intrinsic reparative capacities. Herein, MSCs are engineered with circular mRNA (cmRNA) encoding fibroblast growth factor 18 (FGF18) encapsulated within lipid nanoparticles (LNP) derived from a glycerolipid to facilitate OA healing. A proprietary biodegradable and ionizable glycerolipid, TG6A, with branched tails and five ester bonds, forms LNP exhibiting above 9-fold and 41-fold higher EGFP protein expression in MSCs than commercial LNP from DLin-MC3-DMA and ALC-0315, respectively. The introduction of FGF18 not only augmented the proliferative capacity of MSCs but also upregulated the expression of chondrogenic genes and glycosaminoglycan (GAG) content. Additionally, FGF18 enhanced the production of proteoglycans and type II collagen in chondrocyte pellet cultures in a three-dimensional culture. In an OA rat model, transplantation with FGF18-engineered MSCs remarkably preserved cartilage integrity and facilitated functional repair of cartilage lesions, as evidenced by thicker cartilage layers, reduced histopathological scores, maintenance of zone structure, and incremental type II collagen and extracellular matrix (ECM) deposition. Taken together, our findings suggest that TG6A-based LNP loading with cmRNA for engineering MSCs present an innovative strategy to overcome the current limitations in OA treatment.

Hyaluronic Acid Nanoparticles with Parameters Required for In Vivo Applications: From Synthesis to Parametrization

Hyaluronic acid is an excellent biocompatible material for in vivo applications. Its ability to bind CD44, a cell receptor involved in numerous biological processes, predetermines HA-based nanomaterials as unique carrier for therapeutic and theranostic applications. Although numerous methods for the synthesis of hyaluronic acid nanoparticles (HANPs) are available today, their low reproducibility and wide size distribution hinder the precise assessment of the effect on the organism. A robust and reproducible approach for producing HANPs that meet strict criteria for in vivo applications (e.g., to lung parenchyma) remains challenging. We designed and evaluated four protocols for the preparation of HANPs with those required parameters. The HA molecule was cross-linked by novel combinations of carbodiimide, and four different amine-containing compounds resulted in monodisperse HANPs with a low polydispersity index. By a complex postsynthetic characterization, we confirmed that the prepared HANPs meet the criteria for inhaled therapeutic delivery and other in vivo applications.

Revealing Changes in Celecoxib Nanostructured Lipid Carrier's Bioavailability Using Hyaluronic Acid as an Enhancer by HPLC-MS/MS

Purpose

Oral drug administration is the most common and convenient route, offering good patient compliance but drug solubility limits oral applications. Celecoxib, an insoluble drug, requires continuous high-dose oral administration, which may increase cardiovascular risk. The nanostructured lipid carriers prepared from drugs and lipid excipients can effectively improve drug bioavailability, reduce drug dosage, and lower the risk of adverse reactions.

Methods

In this study, we prepared hyaluronic acid-modified celecoxib nanostructured lipid carriers (HA-NLCs) to improve the bioavailability of celecoxib and reduce or prevent adverse drug reactions. Meanwhile, we successfully constructed a set of FDA-compliant biological sample test methods to investigate the pharmacokinetics of HA-NLCs in rats.

Results

The pharmacokinetic analysis confirmed that HA-NLCs significantly enhanced drug absorption, resulting in an AUC0-t 1.54 times higher than the reference formulation (Celebrex®). Moreover, compared with unmodified nanostructured lipid carriers (CXB-NLCs), HA-NLCs enhance the retention time and improve the drug's half-life in vivo.

Conclusion

HA-NLCs significantly increased the bioavailability of celecoxib. The addition of hyaluronic acid prolonged the drug's in vivo duration of action and reduced the risk of cardiovascular adverse effects associated with the frequent administration of oral celecoxib.

Harmonizing hope: navigating the osteoarthritis melody through the CCL2/CCR2 axis for innovative therapeutic avenues

Osteoarthritis (OA) is characterized by a complex interplay of molecular signals orchestrated by the CCL2/CCR2 axis. The pathogenesis of OA has been revealed to be influenced by a multifaceted effect of CCL2/CCR2 signaling on inflammation, cartilage degradation, and joint homeostasis. The CCL2/CCR2 axis promotes immune cell recruitment and tips the balance toward degeneration by influencing chondrocyte behavior. Insights into these intricate pathways will offer novel therapeutic approaches, paving the way for targeted interventions that may redefine OA management in the future. This review article explores the molecular symphony through the lens of the CCL2/CCR2 axis, providing a harmonious blend of current knowledge and future directions on OA treatment. Furthermore, in this study, through a meticulous review of recent research, the key players and molecular mechanisms that amplify the catabolic cascade within the joint microenvironment are identified, and therapeutic approaches to targeting the CCL2/CCR axis are discussed.

Advancements in pH-Responsive nanoparticles for osteoarthritis treatment: Opportunities and challenges

Osteoarthritis (OA) is a degenerative disease linked to aging and obesity. The global aging population has led to an increasing number of OA patients, imposing a significant economic burden on society. Traditional drugs treatment methods often fail to achieve satisfactory outcomes. With the rapid advancement of nanomaterial delivery systems, numerous studies have focused on utilizing nanomaterials as carriers to achieve efficient OA treatment by effectively loading and delivering bioactive ingredients (e.g., drugs, nucleic acids) tailored to the unique pathological conditions, such as the weakly acidic microenvironment of synovial fluid in OA patients. This review highlights the latest advancements in the use of pH-responsive nanoparticles for OA treatment, emphasizing the principle of targeted drug delivery leveraging the acidic microenvironment of inflamed joints. It further discusses the composition, synthesis, response mechanism, target selection, application, and recent research findings of nanoparticles, while also addressing the challenges and future directions in this promising field.

A Top-Down Design Approach for Generating a Peptide PROTAC Drug Targeting Androgen Receptor for Androgenetic Alopecia Therapy

While large-scale artificial intelligence (AI) models for protein structure prediction and design are advancing rapidly, the translation of deep learning models for practical macromolecular drug development remains limited. This investigation aims to bridge this gap by combining cutting-edge methodologies to create a novel peptide-based PROTAC drug development paradigm. Using ProteinMPNN and RFdiffusion, we identified binding peptides for androgen receptor (AR) and Von Hippel-Lindau (VHL), followed by computational modeling with Alphafold2-multimer and ZDOCK to predict spatial interrelationships. Experimental validation confirmed the designed peptide's binding ability to AR and VHL. Transdermal microneedle patching technology was seamlessly integrated for the peptide PROTAC drug delivery in androgenic alopecia treatment. In summary, our approach provides a generic method for generating peptide PROTACs and offers a practical application for designing potential therapeutic drugs for androgenetic alopecia. This showcases the potential of interdisciplinary approaches in advancing drug development and personalized medicine.

Nanodrugs based on co-delivery strategies to combat cisplatin resistance

Cisplatin (CDDP), as a broad-spectrum anticancer drug, is able to bind to DNA and inhibit cell division. Despite the widespread use of cisplatin since its discovery, cisplatin resistance developed during prolonged chemotherapy, similar to other small molecule chemotherapeutic agents, severely limits its clinical application. Cisplatin resistance in cancer cells is mainly caused by three reasons: DNA repair, decreased cisplatin uptake/increased efflux, and cisplatin inactivation. In earlier combination therapies, the emergence of multidrug resistance (MDR) in cancer cells prevented the achievement of the desired therapeutic effect even with the accurate combination of two chemotherapeutic drugs. Therefore, combination therapy using nanocarriers for co-delivery of drugs is considered to be ideal for alleviating cisplatin resistance and reducing cisplatin-related toxicity in cancer cells. This article provides an overview of the design of cisplatin nano-drugs used to combat cancer cell resistance, elucidates the mechanisms of action of cisplatin and the pathways through which cancer cells develop resistance, and finally discusses the design of drugs and related carriers that can synergistically reduce cancer resistance when combined with cisplatin.

The bioengineering application of hyaluronic acid in tissue regeneration and repair

The multifaceted role of hyaluronic acid (HA) across diverse biomedical disciplines underscores its versatility in tissue regeneration and repair. HA hydrogels employ different crosslinking including chemical (chitosan, collagen), photo- initiation (riboflavin, LAP), enzymatic (HRP/H2O2), and physical interactions (hydrogen bonds, metal coordination). In biophysics and biochemistry, HA's signaling pathways, primarily through CD44 and RHAMM receptors, modulate cell behavior (cell migration; internalization of HA), inflammation, and wound healing. Particularly, smaller HA fragments stimulate inflammatory responses through toll-like receptors, impacting macrophages and cytokine expression. HA's implications in oncology highlight its involvement in tumor progression, metastasis, and treatment. Elevated HA in tumor stroma impacts apoptosis resistance and promotes tumor growth, presenting potential therapeutic targets to halt tumor progression. In orthopedics, HA's presence in synovial fluid aids in osteoarthritis management, as its supplementation alleviates pain, enhances synovial fluid's viscoelastic properties, and promotes cartilage integrity. In ophthalmology, HA's application in dry eye syndrome addresses symptoms by moisturizing the eyes, replenishing tear film deficiencies, and facilitating wound healing. Intravitreal injections and hydrogel-based systems offer versatile approaches for drug delivery and vitreous humor replacement. For skin regeneration and wound healing, HA hydrogel dressings exhibit exceptional properties by promoting moist wound healing and facilitating tissue repair. Integration of advanced regenerative tools like stem cells and solubilized amnion membranes into HA-based systems accelerates wound closure and tissue recovery. Overall, HA's unique properties and interactions render it a promising candidate across diverse biomedical domains, showcasing immense potentials in tissue regeneration and therapeutic interventions. Nevertheless, many detailed cellular and molecular mechanisms of HA and its applications remain unexplored and warrant further investigation.

Development and functional evaluation of a hyaluronic acid coated nano-formulation with kaempferol as a novel intra-articular agent for Knee Osteoarthritis treatment

Knee osteoarthritis (OA) involves articular cartilage degradation driven mainly by inflammation. Kaempferol (KM), known for its anti-inflammatory property, holds potential for OA treatment. This study investigated the potential of hyaluronic acid (HA)-coated gelatin nanoparticles loaded with KM (HA-KM GNP) for treating knee OA. KM was encapsulated into gelatin nanoparticles (KM GNP) and then coated with HA to form HA-KM GNPs. Physical properties were characterized, and biocompatibility and cellular uptake were assessed in rat chondrocytes. Anti-inflammatory and chondrogenic properties were evaluated using IL-1β-stimulated rat chondrocytes, compared with HA-coated nanoparticles without KM (HA GNP) and KM alone. Preclinical efficacy was tested in an anterior cruciate ligament transection (ACLT)-induced knee OA rat model treated with intra-articular injection of HA-KM GNP. Results show spherical HA-KM GNPs (88.62 ± 3.90 nm) with positive surface charge. Encapsulation efficiency was 98.34 % with a sustained release rate of 18 % over 48 h. Non-toxic KM concentration was 2.5 μg/mL. In IL-1β-stimulated OA rat chondrocytes, HA-KM GNP significantly down-regulated RNA expression of IL-1β, TNF-α, COX-2, MMP-9, and MMP-13, while up-regulating SOX9 compared to HA GNP, and KM. In vivo imaging demonstrated significantly higher fluorescence intensity within rat knee joints for 3 hours post HA-KM GNP injection compared with KM GNP (185.2% ± 34.1% vs. 45.0% ± 16.7%). HA-KM GNP demonstrated significant effectiveness in reducing subchondral sclerosis, attenuating inflammation, inhibiting matrix degradation, restoring cartilage thickness, and reducing the severity of OA in the ACLT rat model. In conclusion, HA-KM GNP holds promise for knee OA therapy.

Animal Models of Osteoarthritis: Updated Models and Outcome Measures 2016-2023

Purpose

Osteoarthritis (OA) is a global musculoskeletal disorder that affects primarily the knee and hip joints without any FDA-approved disease-modifying therapies. Animal models are essential research tools in developing therapies for OA; many animal studies have provided data for the initiation of human clinical trials. Despite this, there is still a need for strategies to recapitulate the human experience using animal models to better develop treatments and understand pathogenesis. Since our last review on animal models of osteoarthritis in 2016, there have been exciting updates in OA research and models. The main purpose of this review is to update the latest animal models and key features of studies in OA research.

Method

We used our existing classification method and screened articles in PubMed and bibliographic search for animal OA models between 2016 and 2023. Relevant and high-cited articles were chosen for inclusion in this narrative review.

Results

Recent studies were analyzed and classified. We also identified ex vivo models as an area of ongoing research. Each animal model offers its own benefit in the study of OA and there are a full range of outcome measures that can be assessed. Despite the vast number of models, each has its drawbacks that have limited translating approved therapies for human use.

Conclusion

Depending on the outcome measures and objective of the study, researchers should pick the best model for their work. There have been several exciting studies since 2016 that have taken advantage of regenerative engineering techniques to develop therapies and better understand OA.

Lay Summary

Osteoarthritis (OA) is a chronic debilitating disease without any cure that affects mostly the knee and hip joints and often results in surgical joint replacement. Cartilage protects the joint from mechanical forces and degrades with age or in response to injury. The many contributing causes of OA are still being investigated, and animals are used for preclinical research and to test potential new treatments. A single consensus OA animal model for preclinical studies is non-existent. In this article, we review the many animal models for OA and provide a much-needed update on studies and model development since 2016.

Uncovering the shared neuro-immune-related regulatory mechanisms between spinal cord injury and osteoarthritis

Adults with spinal cord injury (SCI), a destructive neurological injury, have a significantly higher incidence of osteoarthritis (OA), a highly prevalent chronic joint disorder. This study aimed to dissect the neuroimmune-related regulatory mechanisms of SCI and OA using bioinformatics analysis. Using microarray data from the Gene Expression Omnibus database, differentially expressed genes (DEGs) were screened between SCI and sham samples and between OA and control samples. Common DEGs were used to construct a protein-protein interaction (PPI) network. Weighted gene co-expression network analysis (WGCNA) was used to mine SCI- and OA-related modules. Shared miRNAs were identified, and target genes were predicted using the Human MicroRNA Disease Database (HMDD) database. A miRNA-gene-pathway regulatory network was constructed with overlapping genes, miRNAs, and significantly enriched pathways. Finally, the expression of the identified genes and miRNAs was verified using RT-qPCR. In both the SCI and OA groups, 185 common DEGs were identified, and three hub clusters were obtained from the PPI network. WGCNA revealed three SCI-related modules and two OA-related modules. There were 43 overlapping genes between the PPI network clusters and the WGCNA network modules. Seventeen miRNAs shared between patients with SCI and OA were identified. A regulatory network consisting of five genes, six miRNAs, and six signaling pathways was constructed. Upregulation of CD44, TGFBR1, CCR5, and IGF1, while lower levels of miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p in both SCI and OA were successfully verified using RT-qPCR. Our study suggests that a miRNA-gene-pathway network is implicated in the neuroimmune-related regulatory mechanisms of SCI and OA. CD44, TGFBR1, CCR5, and IGF1, and their related miRNAs (miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p) may serve as promising biomarkers and candidate therapeutic targets for SCI and OA.

Harnessing Nanomedicine for Cartilage Repair: Design Considerations and Recent Advances in Biomaterials

Cartilage injuries are escalating worldwide, particularly in aging society. Given its limited self-healing ability, the repair and regeneration of damaged articular cartilage remain formidable challenges. To address this issue, nanomaterials are leveraged to achieve desirable repair outcomes by enhancing mechanical properties, optimizing drug loading and bioavailability, enabling site-specific and targeted delivery, and orchestrating cell activities at the nanoscale. This review presents a comprehensive survey of recent research in nanomedicine for cartilage repair, with a primary focus on biomaterial design considerations and recent advances. The review commences with an introductory overview of the intricate cartilage microenvironment and further delves into key biomaterial design parameters crucial for treating cartilage damage, including microstructure, surface charge, and active targeting. The focal point of this review lies in recent advances in nano drug delivery systems and nanotechnology-enabled 3D matrices for cartilage repair. We discuss the compositions and properties of these nanomaterials and elucidate how these materials impact the regeneration of damaged cartilage. This review underscores the pivotal role of nanotechnology in improving the efficacy of biomaterials utilized for the treatment of cartilage damage.

An injectable cartilage-coating composite with long-term protection, effective lubrication and chondrocyte nourishment for osteoarthritis treatment

The osteoarthritic (OA) environment within articular cartilage poses significant challenges, resulting in chondrocyte dysfunction and cartilage matrix degradation. While intra-articular injections of anti-inflammatory drugs, biomaterials, or bioactive agents have demonstrated some effectiveness, they primarily provide temporary relief from OA pain without arresting OA progression. This study presents an injectable cartilage-coating composite, comprising hyaluronic acid and decellularized cartilage matrix integrated with specific linker polymers. It enhances the material retention, protection, and lubrication on the cartilage surface, thereby providing an effective physical barrier against inflammatory factors and reducing the friction and shear force associated with OA joint movement. Moreover, the composite gradually releases nutrients, nourishing OA chondrocytes, aiding in the recovery of cellular function, promoting cartilage-specific matrix production, and mitigating OA progression in a rat model. Overall, this injectable cartilage-coating composite offers promising potential as an effective cell-free treatment for OA. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) in the articular cartilage leads to chondrocyte dysfunction and cartilage matrix degradation. This study introduces an intra-articular injectable composite material (HDC), composed of decellularized cartilage matrix (dECMs), hyaluronan (HA), and specially designed linker polymers to provide an effective cell-free OA treatment. The linker polymers bind HA and dECMs to form an integrated HDC structure with an enhanced degradation rate, potentially reducing the need for frequent injections and associated trauma. They also enable HDC to specifically coat the cartilage surface, forming a protective and lubricating layer that enhances long-term retention, acts as a barrier against inflammatory factors, and reduces joint movement friction. Furthermore, HDC nourishes OA chondrocytes through gradual nutrient release, aiding cellular function recovery, promoting cartilage-specific matrix production, and mitigating OA progression.

Injectable nanocomposite hydrogels with enhanced lubrication and antioxidant properties for the treatment of osteoarthritis

Osteoarthritis (OA) is a chronic inflammatory joint disease characterized by progressive cartilage degeneration, synovitis, and osteoid formation. In order to effectively treat OA, it is important to block the harmful feedback caused by reactive oxygen species (ROS) produced during joint wear. To address this challenge, we have developed injectable nanocomposite hydrogels composed of polygallate-Mn (PGA-Mn) nanoparticles, oxidized sodium alginate, and gelatin. The inclusion of PGA-Mn not only enhances the mechanical strength of the biohydrogel through a Schiff base reaction with gelatin but also ensures efficient ROS scavenging ability. Importantly, the nanocomposite hydrogel exhibits excellent biocompatibility, allowing it to effectively remove ROS from chondrocytes and reduce the expression of inflammatory factors within the joint. Additionally, the hygroscopic properties of the hydrogel contribute to reduced intra-articular friction and promote the production of cartilage-related proteins, supporting cartilage synthesis. In vivo experiments involving the injection of nanocomposite hydrogels into rat knee joints with an OA model have demonstrated successful reduction of osteophyte formation and protection of cartilage from wear, highlighting the therapeutic potential of this approach for treating OA.

From Nature-Sourced Polysaccharide Particles to Advanced Functional Materials

Polysaccharides constitute over 90% of the carbohydrate mass in nature, which makes them a promising feedstock for manufacturing sustainable materials. Polysaccharide particles (PSPs) are used as effective scavengers, carriers of chemical and biological cargos, and building blocks for the fabrication of macroscopic materials. The biocompatibility and degradability of PSPs are advantageous for their uses as biomaterials with more environmental friendliness. This review highlights the progresses in PSP applications as advanced functional materials, by describing PSP extraction, preparation, and surface functionalization with a variety of functional groups, polymers, nanoparticles, and biologically active species. This review also outlines the fabrication of PSP-derived macroscopic materials, as well as their applications in soft robotics, sensing, scavenging, water harvesting, drug delivery, and bioengineering. The paper is concluded with an outlook providing perspectives in the development and applications of PSP-derived materials.

Self-assembled hyaluronic acid nanoparticles for the topical treatment of inflammatory skin diseases: Beyond drug carriers

Inflammatory skin diseases represent a significant health concern, affecting approximately 20-25% of the global population. These conditions not only reduce an individual's quality of life but also impose a huge burden on both humanity and society. However, addressing these challenges is hindered by their chronic nature, insufficient therapeutic effectiveness, and the propensity for recurrence and adverse side effects. Hyaluronic acid (HA) has emerged as a potential solution to these barriers, owing to its excellent attributes such as biocompatibility, non-toxicity, and targeted drug delivery. However, its practical application has been limited because endogenous hyaluronidase (HYAL) rapidly degrades HA in inflamed skin thus reducing its ability to penetrate deep into the skin. Interestingly, recent research has expanded the role of self-assembled HA-nanoparticles (HA-NPs) beyond drug carriers; they are resistant to HYAL, thereby enabling deep skin penetration, and possess inherent anti-inflammatory properties. Moreover, these abilities can be fine-tuned depending on the conditions during particle synthesis. Additionally, their role as a drug delivery system holds potential for use as a multi-target drug or hybrid drug. In conclusion, this review aims to specifically introduce and highlight the emerging potential of HA-NPs as a topical treatment for inflammatory skin conditions.

Design principles in mechanically adaptable biomaterials for repairing annulus fibrosus rupture: A review

Annulus fibrosus (AF) plays a crucial role in the biomechanical loading of intervertebral disc (IVD). AF is difficult to self-heal when the annulus tears develop, because AF has a unique intricate structure and biologic milieu in vivo. Tissue engineering is promising for repairing AF rupture, but construction of suitable mechanical matching devices or scaffolds is still a grand challenge. To deeply know the varied forces involved in the movement of the native annulus is highly beneficial for designing biomimetic scaffolds to recreate the AF function. In this review, we overview six freedom degrees of forces and adhesion strength on AF tissue. Then, we summarize the mechanical modalities to simulate related forces on AF and to assess the characteristics of biomaterials. We finally outline some current advanced techniques to develop mechanically adaptable biomaterials for AF rupture repair.

Regulating inflammation and apoptosis: A smart microgel gene delivery system for repairing degenerative nucleus pulposus

The progression of intervertebral disc degeneration (IDD) is attributed to the gradual exacerbation of cellular apoptosis and impaired extracellular matrix (ECM) synthesis, both of which are induced by progressive inflammation. Therefore, it is crucial to address the inflammatory microenvironment and rectify the excessive apoptosis of nucleus pulposus cells (NPCs) to achieve intervertebral disc (IVD) regeneration. In this study, we devised a smart microgel gene delivery system that incorporates functionalized gene nanoparticles (NPs) for the purpose of IVD regeneration. siGrem1 was loaded into the NPs to enhance their antiapoptotic ability and protective effects. Furthermore, the encapsulation of HADA further endows the NPs (referred to as HSGN) with targeted delivery and anti-inflammatory effects, as well as reactive oxygen species (ROS) scavenging capacities. To create an microenvironment-responsive microgel system, phenylboronic acid-functionalized microspheres (referred to as M.S.) were fabricated and dynamically loaded with the HSGN. This microgel system (MHSGN), which is highly biocompatible, enables the sustained release of siGrem1, effectively modulating inflammation, scavenging ROS, and alleviating apoptosis in NPCs. These multifunctional capabilities promote the restoration of metabolic homeostasis within the nucleus pulposus ECM, ultimately leading to delayed IDD.

Engineering of targeting antioxidant polypeptide nanopolyplexes for the treatment of acute lung injury

The pathogenesis of acute lung injury (ALI) involves various mechanisms, such as oxidative stress, inflammation, and epithelial cell apoptosis. However, current drug therapies face limitations due to issues like systemic distribution, drug degradation in vivo, and hydrophobicity. To address these challenges, we developed a pH-responsive nano-drug delivery system for delivering antioxidant peptides to treat ALI. In this study, we utilized low molecular weight chitosan (LMWC) and hyaluronic acid (HA) as carrier materials. LMWC carries a positive charge, while HA carries a negative charge. By stirring the two together, the electrostatic adsorption between LMWC and HA yielded aggregated drug carriers. To specifically target the antioxidant drug WNWAD to lung lesions and enhance therapeutic outcomes for ALI, we created a targeted drug delivery system known as HA/LMWC@WNWAD (NPs) through a 12-h stirring process. In our research, we characterized the particle size and drug release of NPs. Additionally, we assessed the targeting ability of NPs. Lastly, we evaluated the improvement of lung injury at the cellular and animal levels to investigate the therapeutic mechanism of this drug targeting delivery system.

Lineage-specific multifunctional double-layer scaffold accelerates the integrated regeneration of cartilage and subchondral bone

Repairing cartilage/subchondral bone defects that involve subchondral bone is a major challenge in clinical practice. Overall, the integrated repair of the structure and function of the osteochondral (OC) unit is very important. Some studies have demonstrated that the differentiation of cartilage is significantly enhanced by reducing the intake of nutrients such as lipids. This study demonstrates that using starvation can effectively optimize the therapeutic effect of bone marrow mesenchymal stem cells (BMSCs)-derived extracellular vesicles (EVs). A hyaluronic acid (HA)-based hydrogel containing starved BMSCs-EVs displayed continuous release for more than 3 weeks and significantly promoted the proliferation and biosynthesis of chondrocytes around the defect regulated by the forkhead-box class O (FOXO) pathway. When combined with vascular inhibitors, the hydrogel inhibited cartilage hypertrophy and facilitated the regeneration of hyaline cartilage. A porous methacrylate gelatine (GelMA)-based hydrogel containing calcium salt loaded with thrombin rapidly promoted haematoma formation upon contact with the bone marrow cavity to quickly block the pores and prevent the blood vessels in the bone marrow cavity from invading the cartilage layer. Furthermore, the haematoma could be used as nutrients to accelerate bone survival. The in vivo experiments demonstrated that the multifunctional lineage-specific hydrogel promoted the integrated regeneration of cartilage/subchondral bone. Thus, this hydrogel may represent a new strategy for osteochondral regeneration and repair.

Hyaluronic acid-empowered nanotheranostics in breast and lung cancers therapy

Nanomedicine application in cancer therapy is an urgency because of inability of current biological therapies for complete removal of tumor cells. The development of smart and novel nanoplatforms for treatment of cancer can provide new insight in tumor suppression. Hyaluronic acid is a biopolymer that can be employed for synthesis of smart nanostructures capable of selective targeting CD44-overexpressing tumor cells. The breast and lung cancers are among the most malignant and common tumors in both females and males that environmental factors, lifestyle and genomic alterations are among the risk factors for their pathogenesis and development. Since etiology of breast and lung tumors is not certain and multiple factors participate in their development, preventative measures have not been completely successful and studies have focused on developing new treatment strategies for them. The aim of current review is to provide a comprehensive discussion about application of hyaluronic acid-based nanostructures for treatment of breast and lung cancers. The main reason of using hyaluronic acid-based nanoparticles is their ability in targeting breast and lung cancers in a selective way due to upregulation of CD44 receptor on their surface. Moreover, nanocarriers developed from hyaluronic acid or functionalized with hyaluronic acid have high biocompatibility and their safety is appreciated. The drugs and genes used for treatment of breast and lung cancers lack specific accumulation at cancer site and their cytotoxicity is low, but hyaluronic acid-based nanostructures provide their targeted delivery to tumor site and by increasing internalization of drugs and genes in breast and lung tumor cells, they improve their therapeutic index. Furthermore, hyaluronic acid-based nanostructures can be used for phototherapy-mediated breast and lung cancers ablation. The stimuli-responsive and smart kinds of hyaluronic acid-based nanostructures such as pH- and light-responsive can increase selective targeting of breast and lung cancers.

Therapeutics of osteoarthritis and pharmacological mechanisms: A focus on RANK/RANKL signaling

Osteoarthritis (OA) is a chronic degenerative disease afflicting millions globally. Despite the development of numerous pharmacological treatments for OA, a substantial unmet need for effective therapies persists. The RANK/RANKL signaling pathway has emerged as a promising therapeutic target for OA, owing to its pivotal role in regulating osteoclast differentiation and activity. In this comprehensive review, we aim to elucidate the relevant mechanisms of OA mediated by RANK/RANKL signaling, including bone remodeling, inflammation, cartilage degradation, osteophyte formation, and pain sensitization. Furthermore, we discuss and summarize the cutting-edge strategies targeting RANK/RANKL signaling for OA therapy, encompassing approaches such as gene-based interventions and biomaterials-aided pharmacotherapy. In addition, we highlight the prevailing challenges associated with pharmacological OA treatments and explore potential future directions, approached through a clinical-translational lens.