Chondroitin sulfate-functionalized lipid nanoreservoirs: a novel cartilage-targeting approach for intra-articular delivery of cassic acid for osteoarthritis treatment

Harnessing the multifunctionality of lipid-based drug delivery systems for the local treatment of osteoarthritis

Osteoarthritis (OA) is a widespread joint condition affecting millions globally, presenting a growing socioeconomic burden thus making the development of more effective therapeutic strategies crucial. This review emphasizes recent advancements in lipid-based drug delivery systems (DDSs) for intra-articular administration of OA therapeutics, encompassing non-steroidal anti-inflammatory drugs, corticosteroids, small molecule disease-modifying OA drugs, and RNA therapeutics. Liposomes, lipid nanoparticles, lipidic mesophases, extracellular vesicles and composite systems exhibit enhanced stability, targeted delivery, and extended joint retention, which contribute to improved therapeutic outcomes and minimized systemic drug exposure. Although active targeting strategies hold promise, further research is needed to assess their targeting efficiency in physiologically relevant conditions. Simultaneously, multifunctional DDSs capable of delivering combinations of distinct therapeutic classes offer synergistic effects and superior OA treatment outcomes. The development of such long-acting systems that resist rapid clearance from the joint space is crucial, where particle size and targeting capabilities emerge as vital factors. Additionally, combining cartilage lubrication properties with sustained drug delivery has demonstrated potential in animal models, meriting further investigation in human clinical trials. This review highlights the crucial need for direct, head-to-head comparisons of novel DDSs with standard treatments, particularly within the same drug class. These comparisons are essential in accurately evaluating their effectiveness, safety, and clinical applicability, and are set to significantly shape the future of OA therapy.

Chondroitin Sulfate Supplements for Osteoarthritis: A Critical Review

Over the years, chondroitin sulfate (CS) has been used as a slow-acting drug for the treatment of osteoarthritis, for the reduction of pain and improvement of function, and for its disease-modifying properties by limiting cartilage volume loss and joint space narrowing progression. However, there have been inconsistencies in published trials regarding clinical efficacy, with reports of a lack of significant effects compared to placebo. The therapeutic effects of chondroitin sulfate may depend on many variables, such as the source of origin, purity, and contamination with by-products. Another source of confusion may be related to the fact that CS is commonly combined with glucosamine, which makes it challenging to isolate the specific contribution of chondroitin to the therapeutic outcome. This is aggravated by the fact that CS supplements, used in many countries, are not regulated, and labels wrongly claim high levels of purity. Many of these inferior CS products may have been used in clinical trials, which may have had limited but significant results. This has led to recent recommendations to opt for higher-purity pharmacologic-grade CS for the treatment of OA. This article aims to provide an up-to-date view of the current literature regarding the biological effects and efficacy of CS and discusses the quality of available chondroitin sulfate supplements and the current direction in CS investigation. This review concludes that pharmacologic-grade CS supplements may have clinically significant benefits when properly standardized; however, high-quality evidence from properly designed clinical trials is still needed to draw definitive conclusions about clinical efficacy in osteoarthritis.

Bone/cartilage targeted hydrogel: Strategies and applications

The skeletal system is responsible for weight-bearing, organ protection, and movement. Bone diseases caused by trauma, infection, and aging can seriously affect a patient's quality of life. Bone targeted biomaterials are suitable for the treatment of bone diseases. Biomaterials with bone-targeted properties can improve drug utilization and reduce side effects. A large number of bone-targeted micro-nano materials have been developed. However, only a few studies addressed bone-targeted hydrogel. The large size of hydrogel makes it difficult to achieve systematic targeting. However, local targeted hydrogel still has significant prospects. Molecules in bone/cartilage extracellular matrix and bone cells provide binding sites for bone-targeted hydrogel. Drug delivery systems featuring microgels with targeting properties is a key construction strategy for bone-targeted hydrogel. Besides, injectable hydrogel drug depot carrying bone-targeted drugs is another strategy. In this review, we summarize the bone-targeted hydrogel through application environment, construction strategies and disease applications. We hope this article will provide a reference for the development of bone-targeted hydrogels. We also hope this article could increase awareness of bone-targeted materials.

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Introducing the microenvironment and target molecules in different parts of long bones.

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Summarizing the construction strategy of micro/nanoparticle hydrogel with bone targeting properties.

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Summarizing the construction strategy of hydrogel based depot carrying bone-targeted drugs.

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Reporting the application and effect of bone targeting hydrogel in common bone diseases.

Osteoarthritis models: From animals to tissue engineering

Osteoarthritis (OA) is a chronic degenerative osteoarthropathy. Although it has been revealed that a variety of factors can cause or aggravate the symptoms of OA, the pathogenic mechanisms of OA remain unknown. Reliable OA models that accurately reflect human OA disease are crucial for studies on the pathogenic mechanism of OA and therapeutic drug evaluation. This review first demonstrated the importance of OA models by briefly introducing the OA pathological features and the current limitations in the pathogenesis and treatment of OA. Then, it mainly discusses the development of different OA models, including animal and engineered models, highlighting their advantages and disadvantages from the perspective of pathogenesis and pathology analysis. In particular, the state-of-the-art engineered models and their potential were emphasized, as they may represent the future direction in the development of OA models. Finally, the challenges in obtaining reliable OA models are also discussed, and possible future directions are outlined to shed some light on this area.

Nanodevices for deep cartilage penetration

Osteoarthritis (OA) is a degenerative joint disease and is the main cause of chronic pain and functional disability in adults. Articular cartilage is a hydrated soft tissue that is composed of normally quiescent chondrocytes at a low density, a dense network of collagen fibrils with a pore size of 60-200 nm, and aggrecan proteoglycans with high-density negative charge. Although certain drugs, nucleic acids, and proteins have the potential to slow the progression of OA and restore the joints, these treatments have not been clinically applied owing to the lack of an effective delivery system capable of breaking through the cartilage barrier. Recently, the development of nanotechnology for delivery systems renders new ideas and treatment methods viable in overcoming the limited penetration. In this review, we focus on current research on such applications of nanotechnology, including exosomes, protein-based cationic nanocarriers, cationic liposomes/solid lipid nanoparticles, amino acid-based nanocarriers, polyamide derivatives-based nanocarriers, manganese dioxide, and carbon nanotubes. Exosomes are the smallest known nanoscale extracellular vesicles, and they can quickly deliver nucleic acids or proteins to the required depth. Through electrostatic interactions, nanocarriers with appropriate balance in cationic property and particle size have a strong ability to penetrate cartilage. Although substantial preclinical evidence has been obtained, further optimization is necessary for clinical transformation. STATEMENT OF SIGNIFICANCE: The dense cartilage matrix with high-negative charge was associated with reduced therapeutic effect in osteoarthritis patients with deep pathological changes. However, a systematic review in nanodevices for deep cartilage penetration is still lacking. Current approaches to assure penetration of nanosystems into the depth of cartilage were reviewed, including nanoscale extracellular vesicles from different cell lines and nanocarriers with appropriate balance in cationic property and size particle. Moreover, nanodevices entering clinical trials and further optimization were also discussed, providing important guiding significance to future research.

Development and Evaluation of Novel Leflunomide SPION Bioemulsomes for the Intra-Articular Treatment of Arthritis

Systemic treatments for rheumatoid arthritis are associated with many side effects. This study aimed to minimize the side effects associated with the systemic administration of leflunomide (LEF) by formulating LEF-loaded emulsomes (EMLs) for intra-articular administration. Additionally, EMLs were loaded with supramagnetic nanoparticles (SPIONs) to enhance joint localization, where a magnet was placed on the joint area after intra-articular administration. Full in vitro characterization, including colloidal characteristics, entrapment efficiency, and in vitro release were conducted besides the in vivo evaluation in rats with adjuvant-induced arthritis. In vivo study included joint diameter measurement, X-ray radiographic analysis, RT-PCR analysis, Western blotting, ELISA for inflammatory markers, and histopathological examination of dissected joints. The particle size and entrapment efficiency of the selected LEF SPION EMLs were 198.2 nm and 83.7%, respectively. The EMLs exhibited sustained release for 24 h. Moreover, in vivo evaluation revealed LEF SPION EMLs to be superior to the LEF suspension, likely due to the increase in LEF solubility by nanoencapsulation that improved the pharmacological effects and the use of SPION that ensured the localization of EMLs in the intra-articular cavity upon administration.