Intra-articular treatment with hyaluronic acid associated with gold nanoparticles in a mechanical osteoarthritis model in Wistar rats

Multiscale metal-based nanocomposites for bone and joint disease therapies

Bone and joint diseases are debilitating conditions that can result in significant functional impairment or even permanent disability. Multiscale metal-based nanocomposites, which integrate hierarchical structures ranging from the nanoscale to the macroscale, have emerged as a promising solution to this challenge. These materials combine the unique properties of metal-based nanoparticles (MNPs), such as enzyme-like activities, stimuli responsiveness, and photothermal conversion, with advanced manufacturing techniques, such as 3D printing and biohybrid systems. The integration of MNPs within polymer or ceramic matrices offers a degree of control over the mechanical strength, antimicrobial efficacy, and the manner of drug delivery, whilst concomitantly promoting the processes of osteogenesis and chondrogenesis. This review highlights breakthroughs in stimulus-responsive MNPs (e.g., photo-, magnetically-, or pH-activated systems) for on-demand therapy and their integration with biocomposite hybrids containing cells or extracellular vesicles to mimic the native tissue microenvironment. The applications of these composites are extensive, ranging from bone defects, infections, tumors, to degenerative joint diseases. The review emphasizes the enhanced load-bearing capacity, bioactivity, and tissue integration that can be achieved through hierarchical designs. Notwithstanding the potential of these applications, significant barriers to progress persist, including challenges related to long-term biocompatibility, regulatory hurdles, and scalable manufacturing. Finally, we propose future directions, including machine learning-guided design and patient-specific biomanufacturing to accelerate clinical translation. Multiscale metal-based nanocomposites, which bridge nanoscale innovations with macroscale functionality, are a revolutionary force in the field of biomedical engineering, providing personalized regenerative solutions for bone and joint diseases.

Pulsed ultrasound and moderate exercise accelerate bone healing in an experimental tibial fracture model: biochemical, radiological and biomechanical evidence

Currently, therapeutic strategies involving mechanical stress play a key role in fracture consolidation. However, no literary evidence exists regarding the combined effects of low-intensity pulsed ultrasound (LIPUS) and moderate aerobic exercise. This study aimed to investigate the effects of LIPUS and moderate aerobic exercise on bone consolidation in 48 male Wistar rats. The animals were divided into four groups (n = 12 per group): Bone Fracture (BF); BF + LIPUS; BF + Exercise (Ex); BF + Ex + LIPUS. A transverse osteotomy with Kirschner wire fixation was performed, followed by therapeutic interventions for 19 days, three times a week. LIPUS was applied for 10 min (1.5 MHz, 0.4 W/cm2, 3 cm2 area), and aerobic exercise lasted 30 min/day with progressive speed. Radiographic analyses were conducted on days 1, 12, and 24 post-fracture, and euthanasia occurred 72 h after the final session. The combined group exhibited improved radiographic scores and increased birefringent collagen fibers. IL-4, IL-10, and TGF-β levels were significantly higher in treated groups, particularly the combined intervention. Additionally, oxidative stress markers showed reduced nitrite levels, controlled sulfhydryl oxidation, and enhanced SOD and GSH activity. Biomechanically, the combined group tolerated higher loads and demonstrated superior deformation capacity and tissue elasticity. The combination of aerobic exercise and LIPUS enhanced radiographic healing, modulated inflammation, reduced oxidative stress, and improved mechanical properties, supporting its potential for fracture rehabilitation.

Intraarticular gold for knee osteoarthritis: An ancillary analysis of biomarkers and outcome of a pilot study

Objective

In a previous pilot study, we have shown that intraarticular gold micro-particles can reduce knee osteoarthritis (KOA) pain at two years follow-up. Proteomic changes in serum and synovial fluid within eight weeks were associated with multiple inflammatory and immunological processes. The relation between the different biomarkers and the outcome measures is not known. We hypothesized that improvement in pain and function were associated with specific groups of biomarkers. We present the integrative analyses between proteomic biomarkers and outcomes.

Design

A cohort of 30 patients, with moderate KOA, were included. Using the patients' synovial fluid as the carrier, 20 ​mg gold microparticles were injected intraarticularly. Clinical outcome measures at inclusion, 8 weeks, and 2 years, were the PainDetect questionnaire, WOMAC pain, stiffness, and function. In addition, Quantitative Sensory Testing, Pain Pressure Threshold, Temporal Summation, Conditioned Pain Modulation, and pain diary were assessed at inclusion and after 8 weeks. Proteomic analysis was performed on SF and blood samples before and after 8 weeks of treatment.

Results

Linear combinations of serum or synovial biomarkers changed significantly alongside the effect measures and PainDetect scores following gold micro-particle treatment. Of particular interest was identifying multiple members of a molecular complex that is suggestive of neural tissue regeneration and modulation following gold micro-particle treatment.

Conclusions

Gold microparticles are a possible future option for the treatment of knee osteoarthritis. The treatment triggers putative regenerative and inflammation-modulating molecular mechanisms.

Drug Delivery Strategies and Nanozyme Technologies to Overcome Limitations for Targeting Oxidative Stress in Osteoarthritis

Oxidative stress is an important, but elusive, therapeutic target for osteoarthritis (OA). Antioxidant strategies that target oxidative stress through the elimination of reactive oxygen species (ROS) have been widely evaluated for OA but are limited by the physiological characteristics of the joint. Current hallmarks in antioxidant treatment strategies include poor bioavailability, poor stability, and poor retention in the joint. For example, oral intake of exogenous antioxidants has limited access to the joint space, and intra-articular injections require frequent dosing to provide therapeutic effects. Advancements in ROS-scavenging nanomaterials, also known as nanozymes, leverage bioactive material properties to improve delivery and retention. Material properties of nanozymes can be tuned to overcome physiological barriers in the knee. However, the clinical application of these nanozymes is still limited, and studies to understand their utility in treating OA are still in their infancy. The objective of this review is to evaluate current antioxidant treatment strategies and the development of nanozymes as a potential alternative to conventional small molecules and enzymes.

The effectiveness of treadmill and swimming exercise in an animal model of osteoarthritis

Introduction: Osteoarthritis (OA) is considered an inflammatory and degenerative joint disease, characterized by loss of hyaline joint cartilage and adjacent bone remodeling with the formation of osteophytes, accompanied by various degrees of functional limitation and reduction in the quality of life of individuals. The objective of this work was to investigate the effects of treatment with physical exercise on the treadmill and swimming in an animal model of osteoarthritis. Methods: Forty-eight male Wistar rats were divided (n=12 per group): Sham (S); Osteoarthritis (OA); Osteoarthritis + Treadmill (OA + T); Osteoarthritis + Swimming (OA + S). The mechanical model of OA was induced by median meniscectomy. Thirty days later, the animals started the physical exercise protocols. Both protocols were performed at moderate intensity. Forty-eight hours after the end of the exercise protocols, all animals were anesthetized and euthanized for histological, molecular, and biochemical parameters analysis. Results: Physical exercise performed on a treadmill was more effective in attenuating the action of pro-inflammatory cytokines (IFN-γ, TNF-α, IL1-β, and IL6) and positively regulating anti-inflammatories such as IL4, IL10, and TGF-β in relation to other groups. Discussion: In addition to maintaining a more balanced oxi-reductive environment within the joint, treadmill exercise provided a more satisfactory morphological outcome regarding the number of chondrocytes in the histological evaluation. As an outcome, better results were found in groups submitted to exercise, mostly treadmill exercise.

Single Injection of Cross-Linked Hyaluronate in Knee Osteoarthritis: A 52-Week Double-Blind Randomized Controlled Trial

Background: to compare the 52-week effectiveness and safety between HYAJOINT Plus (HJP) and Durolane in knee osteoarthritis (OA) treatment. Methods: consecutive patients received a single injection of 3 mL HJP or Durolane. The primary outcome was a visual analog scale (VAS) pain measurement at 26 weeks post-injection. Secondary outcomes included other clinical, satisfaction, and safety assessments for 52 weeks. Results: 142 patients were equally randomized. At week 26, the HJP group had less VAS pain than the Durolane group (18.1 ± 9.5 versus 24.4 ± 14.0, p = 0.001). Both groups showed improvement in their VAS pain and stiffness scores, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and total scores for 52 weeks after injection (p < 0.001). However, the HJP group showed lower VAS pain and stiffness scores, reduced WOMAC pain and stiffness scores, a shorter Timed “Up & Go” (TUG) time, and a higher satisfaction score than the Durolane group for 39 weeks (p < 0.05). Only mild and self-limited adverse events occurred (40.8%). Conclusion: While a single injection of either HJP or Durolane is safe and effective for at least 52 weeks, HJP provided superior improvement in terms of VAS pain and stiffness scores, WOMAC pain and stiffness scores, and satisfaction score within 39 weeks of treatment.